Article

ISSN 0006-2979, Biochemistry (Moscow), 2025, Vol. 90, No. 12, pp. 1789-1810 © Pleiades Publishing, Ltd., 2025.

Russian Text © The Author(s), 2025, published in Biokhimiya, 2025, Vol. 90, No. 12, pp. 1917-1940.

1789

REVIEW

-Dependent Mitochondrial Permeability

Transition Pore: Structure, Properties,

and Role in Cellular Pathophysiology

Konstantin N. Belosludtsev

1,2,a

*, Mikhail V. Dubinin

, and Natalia V. Belosludtseva

Mari State University, 424000 Yoshkar-Ola, Mari El Republic, Russia

Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences,

142290 Pushchino, Moscow Region, Russia

e-mail: bekonik@gmail.com

Received July 30, 2025

Revised September 9, 2025

Accepted September 22, 2025

Abstract— The Mitochondrial Permeability Transition pore(MPT pore) activated by Ca

ions is a phenomenon

that has long been the subject of intense study. Cyclophilin D-dependent opening of the MPT pore in mito-

chondria in response to calcium overload and oxidative stress leads to swelling of the mitochondrial matrix,

depolarization of the inner membrane and dysregulation of ion homeostasis. These processes are accompanied

by damage to mitochondrial membranes and, ultimately, to cell death. Despite decades of research, the molecular

identity of the MPT pore remains unclear. Currently, the inner membrane proteins– ATP synthase and adenine

nucleotide translocator(ANT)– are considered to be its key structural components, along with the regulatory

protein cyclophilinD. The involvement of the MPT pore in the progression of various pathological conditions

and diseases, as well as in a number of physiological processes, such as the regulation of cellular bioenergetics

and rapid release of Ca

, is widely discussed. This review summarizes modern molecular genetic data on the

putative structure of the MPT pore, traces the evolution of views on its functioning– from interpreting it as

a simple experimental artifact to its recognition as a putative key regulator of energy metabolism– and also

considers the mechanisms of its regulation and its multifaceted pathophysiological role.

DOI: 10.1134/S0006297925602369

Keywords: MPT pore, mitochondria, Ca

, cyclophilinD, adenine nucleotide translocator, F

–ATP synthase, cell

death, neurodegenerative diseases, neuromuscular diseases, diabetes mellitus

* To whom correspondence should be addressed.

INTRODUCTION

Mitochondria are organelles that perform a wide

range of functions in eukaryotic cells. They are the

primary energy generators in most types of cells, they

participate in the regulation of ion homeostasis and

thermogenesis, and their production of reactive oxy-

gen species (ROS) is closely linked to aging and cell

death. However, one of the most intriguing and enig-

matic phenomena associated with these organelles is

the formation and functioning of the Mitochondrial

Permeability Transition pore (MPT pore), which is

formed by a complex of mitochondrial proteins under

a wide range of pathophysiological conditions.

The MPT pore is a megachannel formed in the

outer and inner mitochondrial membranes as a re-

sult of exposure to high concentrations of intracel-

lular Ca

, oxidative stress and other inducers [1].

Despite more than 70years of studying this phenom-

enon, the exact molecular structure of the MPT pore

has not been established yet. The main difficulty lies

in identifying the protein components that form the

pore in the inner mitochondrial membrane. Current-

ly, the most abundant proteins of the inner mitochon-

drial membrane are traditionally considered as such

components, specifically the F

–ATP synthase (com-

plex  V) and adenine nucleotide translocator (ANT)

[2, 3]. At the same time, cyclophilin  D, the key reg-

ulator of the MPT pore, as well as the proteins and

protein subunits involved in the formation of the

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pore complex in the intermembrane space and the

outer membrane of organelles, have been discussed

quite rarely in recent years.

The pathophysiological significance of MPT pore

formation in mitochondria is currently undisputed

and highlights the dual role of these organelles in

cell life and death. It is believed that a prolonged

open state of the MPT pore leads to mitochondrial

and cell death, whereas its short-term “flickering”

opening facilitates the removal of excess Ca

ions

from the mitochondria into the cytoplasm, protecting

cells from the damaging effects of calcium overload

on organelles [3-7].

Based on existing observations, new natural and

synthetic modulators of the MPT pore are being ac-

tively investigated, and genetic manipulations of

known components of the pore complex are being

conducted in model systems. This allows to establish

of a link between the functioning of the pore in mi-

tochondria and the development of various cellular

pathologies. This review analyzes the current state

of research regarding the mechanisms of MPT pore

formation, regulation and functioning, as well as the

prerequisites that have led to the current under-

standing of the nature of this phenomenon in cells,

its physiological and pathological role, and key unre-

solved issues.

THE HISTORY OF PORE STRUCTURE STUDIES

The history of studying the mitochondrial pore

had started long before the term “mitochondrial per-

meability transition” (Fig.  1) was coined. As early as

the 1950s, it was discovered that mitochondria have

the ability to swell, which leads to impaired ATP syn-

thesis [8, 9]. However, the observed mitochondrial

permeabilization was thought to be either an in  vitro

artifact or a consequence of nonspecific damage

to their inner membrane by phospholipase  A

  [10].

 was found to activate phospholipase  A

, whose

hydrolytic activity results in the accumulation of “de-

fects” – lysophospholipids and free fatty acids – in

mitochondrial membranes. These were believed to be

the primary cause of changes in mitochondrial mem-

brane permeability[11]. However, this hypothesis did

not explain why rapid and dramatic swelling of mi-

tochondria occurs if the accumulation of membrane

defects associated with phospholipase  A

activity oc-

curs gradually. However, at the turn of the 21st centu-

ry, studies based on this hypothesis were conducted,

resulting in the discovery of a new type of mitochon-

drial pore – a lipid pore inducible by saturated fatty

acids and Ca

 [12, 13].

In the late 1970s, permeabilization of the inner

mitochondrial membrane was described in detail[14-

16]. It was found that when Ca

ions accumulate in

mitochondria, their inner membrane becomes per-

meable to hydrophilic compounds with a molecular

weight of up to 1.5  kDa, resulting in swelling of the

organelles. The influence of the major metabolites

on this process was studied, and regulation of inner

membrane permeabilization was demonstrated. Based

on these studies, it was suggested that a non-selec-

tive Ca

-dependent channel is formed in the mito-

chondrial membrane in the presence of Ca

ions,

Fig. 1. Timeline of MPT pore research. ANT – adenine nucleotide translocator.

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which can be inhibited by chelating agents. Since

the molecular nature of the channel remained un-

known, the authors proposed the term “permeability

transition” to describe this phenomenon (meaning a

sharp non-specific change in permeability). Since the

change occurred abruptly according to the “all or

nothing” principle[1,14], it was discussed specifically

as a “transition” (and, subsequently, the mitochondri-

al pore) and not a change in mitochondrial permea-

bility, in order to emphasize the transitive nature of

the phenomenon.

In the late 1980s, a high-affinity inhibitor of the

mitochondrial pore, the cyclic undecapeptide cyclo-

sporin  A(CsA) was discovered. It completely inhibited

the MPT pore opening at submicromolar concentra-

tions [17, 18]. It was established that CsA binds to

the mitochondrial matrix protein, peptidyl prolyl cis/

trans isomerase cyclophilin  D [19]. This discovery fi-

nally confirmed the concept of the protein nature of

the mitochondrial pore.

It was initially believed that the target of cyclo-

philin D and the channel component of the pore is

the adenine nucleotide translocator, the predominant

protein of the inner mitochondrial membrane respon-

sible for the antiport of ADP and ATP. The prerequi-

sites for this were discovered back in the 1970s, when

it became clear that the ANT modulators carboxya-

tractylate and bongkrekic acid activate and inhibit

-dependent mitochondrial swelling, respective-

ly [14]. Later, Halestrap and Davidson [20] proposed

a mechanism of action for these inhibitors, according

to which carboxyatractylate stabilized ANT in the cy-

tosolic(c) conformation, and bongkrekic acid– in the

matrix(m) conformation[20]. The hypothesis of a key

role for ANT existed until the mid-2000s, when it was

discovered that ANT is not an essential component of

the MPT pore. In mitochondria of mice with genetic

knockout of the first and second ANT isoforms (ANT1

and ANT2), the MPT pore opened and remained sen-

sitive to cyclosporin A [21].

The search for new channel components of the

MPT pore led to suggestions that such a component

could be a phosphate transporter, and, later, a mito-

chondrial ATP synthase [22, 23]. These proteins have

a common feature of being able to interact with cy-

clophilin  D. However, interest in the phosphate trans-

porter quickly became irrelevant, since its knockdown

or overexpression did not affect pore opening.

Mitochondrial ATP synthase is currently con-

sidered a key component of the MPT pore. Its in-

volvement (or the involvement of individual ATP

synthase subunits) in membrane permeabilization

has been demonstrated by various methods. Sever-

al models for the transformation of ATP synthase

into the MPT pore have been proposed [3]. How-

ever, ANT has recently come to be regarded as an

important component of the MPT pore once more,

responsible for its low-conductance mode of oper-

ation [3].

However, even today we can only discuss a hy-

pothetical structure of the MPT pore. This is primar-

ily due to the limitations of current methodological

approaches.

MPT PORE STRUCTURE

According to current concepts, the mitochondrial

pore is a large protein megachannel formed in the

outer and inner mitochondrial membranes. Depending

on the conditions, the size of the MPT pore can vary

from a small non-selective ion channel to a large pore

with high conductivity (up to 1000pS), through which

ions and hydrophilic molecules with a mass of up to

1.5  kDa can penetrate. Prolonged MPT pore opening

leads to suppression of mitochondrial energy metab-

olism, disruption of ion homeostasis and a drop in

mitochondrial membrane potential. Furthermore, the

entry of osmotically active metabolites into the mito-

chondrial matrix due to MPT pore opening leads to

swelling, followed by rupture of the outer mitochon-

drial membrane. All this, along with the release of

proapoptotic proteins from mitochondria, can lead to

organelle destruction and cell death [1, 3, 7, 12, 24].

These mechanisms of cell death, mediated by the

opening of the mitochondrial pore, play a key role

in the pathogenesis of numerous diseases associated

with ischemic damage to organs and tissues, neuro-

degenerative diseases, aging, etc. At the same time,

the temporary opening of the MPT pore, character-

ized by a low-conductivity state, is of physiological

significance for the cell. This type of pore is involved

in the unloading of Ca

ions from mitochondria, a

decrease in ROS production and regulation of bio-

energetic metabolism [6,  24,  25]. Activation of the

pore is believed to be associated primarily with an

increase in Ca

concentration in the mitochondrial

matrix, development of oxidative stress, an increase

in cyclophilin D levels and a decrease in the pool of

adenine nucleotides. At the same time, di- and triva-

lent cations, adenine nucleotides, SH-reducing agents

and cyclophilinD inhibitors suppress MPT pore open-

ing. More details on this can be found in the review

by Zoratti and Szabo [1].

The abovementioned facts make it clear that

MPT pore formation in mitochondria is a complexly

regulated process that may involve a large number

of proteins. Indeed, current models suggest a multi-

protein nature of the pore, with ANT, ATP synthase,

cyclophilin  D and other proteins forming a dynamic

“sensory cluster” that adapts to particular conditions

in a cell (Fig.  2) [2, 3].

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Fig. 2. The proteins forming the MPT pore in mitochondria and their transformation into pore channels under the influence

of Ca

ions and/or oxidative stress. Fluxes of osmotically active molecules through the pore channels in the inner and

outer membranes upon pore induction are shown. PDB IDs used: ANT– 1OKC; ATP synthase (both) – 6RD4; VDAC – 2JK4;

CypD – 5CBV. Descriptions are given in the text. ANT – adenine nucleotide translocator; VDAC – voltage-dependent anion

channel of the outer mitochondrial membrane; CypD– cyclophilin D.

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When describing the mitochondrial pore model,

three groups of proteins can be distinguished: the

obligatory regulator – cyclophilin  D; hypothetical

channels of the inner membrane pore – ANT and

ATP synthase; auxiliary proteins, which include

VDAC (voltage-dependent anion channels of the out-

er mitochondrial membrane), TSPO(translocator pro-

tein, also known as the peripheral benzodiazepine

receptor), mitochondrial creatine kinase, mitochon-

drial hexokinase and a number of other proteins.

Cyclophilin  D is a key regulator of the MPT pore.

Cyclophilin  D is a protein belonging to the CsA-sensi-

tive peptidyl prolyl cis/trans isomerase family capable

of catalyzing the isomerization of proline residues, a

rate-limiting step in protein folding [26]. All proteins

of this family contain a highly conserved cyclophi-

lin-like domain consisting of 8 antiparallel β-sheets

that form a hydrophobic core with the catalytic cen-

ter and other functional regions [19]. Cyclophilin  D

is encoded by the Ppif gene, the mature protein is

localized in the mitochondrial matrix and contains

178 amino acid residues (19  kDa) [19].

Cyclophilin  D is able to interact with a large

number of various transporters which are associat-

ed with membrane proteins, including ATP synthase,

ANT, respiratory chain complex  III, the anti-apoptotic

Bcl2 protein and the key metabolic protein kinases

GSK-3β and Akt2 [19, 27-29]. Due to this, cyclophil-

in D is able to regulate the formation of various mi-

tochondrial supercomplexes. However, its most well-

described function is regulation of MPT pore forma-

tion. Cyclophilin D modulates pore formation by re-

ducing the threshold level of calcium load required

for pore opening in mitochondria; this requires the

interaction of cyclophilin  D with ATP synthase or ANT,

which form a channel in the pore complex[2,3]. This

effect is suppressed in the presence of cyclosporin  A,

which is believed to cause dissociation of cyclophilin

D from channel proteins[20]. Mitochondria from var-

ious tissues of mice with the knocked out Ppif gene

(and, consequentially, lacking the interaction of pore

proteins with cyclophilin  D) were more resistant to

overload, and the addition of CsA had no inhib-

itory effect in this case. At the same time, overex-

pression of the Ppif gene caused an increase in Ca

dependent mitochondrial swelling and cell death[30].

The exact mechanism of modulation of MPT pore

formation involving cyclophilin  D has not been ful-

ly established. Early studies demonstrated that MPT

pore formation requires interaction of cyclophilin  D

with ANT and VDAC proteins [29]. However, it is

now recognized that cyclophilin D binds primarily

to ATP synthase [3, 28] (Fig.  2). In the ATP synthase

complex, cyclophilin  D interacts with OSCP (oligomy-

cin sensitivity conferring protein), which appears to

be involved in peripheral stalk formation [23, 28].

The issue of whether the enzymatic activity of cyclo-

philin  D is required also remains debatable. It was

initially assumed that cyclophilin  D induces MPT

pore formation independently of its peptidyl prolyl

cis/trans isomerase activity  [31]. However, fibroblasts

with inactivated cyclophilin  D (Arg96Gly substitution)

were insensitive to oxidative stress induction, simi-

lar to what was observed in cells with a knockout

of this protein  [30]. This suggests that the enzymatic

activity of the protein does facilitate MPT pore acti-

vation. Furthermore, peptidyl prolyl cis/trans isomer-

ase activity correlates with increased self-assembly of

ATP synthasomes (a supercomplex consisting of ATP

synthase, ANT and a phosphate transporter) in vari-

ous tissues and the formation of highly ordered ATP

synthase oligomeric structures, thereby reducing the

likelihood of MPT pore formation [32].

The ability of cyclophilin  D to modulate MPT

pore opening is provided in the cell by mechanisms

of post-translational protein modification [19]. For

example, acetylation of Lys138 stimulates MPT pore

formation [33]. It is believed that Lys138 is localized

in the catalytic site of the protein and is involved in

the interaction with OSCP [23]. GSK-3β increases cy-

clophilin  D binding to OSCP and stimulates MPT pore

opening by phosphorylating Ser162 [34, 35]. Cleavage

of the N-terminal region of cyclophilin  D by calpain  1

can also contribute to an increase in the probability

of MPT pore opening by enhancing the interaction

with OSCP [36]. Oxidative modification of cyclophil-

in  D at cysteine residues (Cys174(C203) in particular)

is involved in the process of activation of MPT pore

formation in the presence of oxidative stress induc-

ers [37].

ANT and ATP synthase as channel proteins of

the pore complex. The adenine nucleotide transloca-

tor is a protein of the SLC25 family of mitochondri-

al transporters that transport metabolites, inorganic

ions and cofactors [38]. ANT exchanges matrix ATP

for cytoplasmic ADP across the inner mitochondrial

membrane [39]. It is also believed that one of the

alternative functions of ANT is fatty acid-catalyzed

proton transfer, which ensures uncoupling of oxida-

tive phosphorylation. In humans, 4  ANT isoforms are

present (while mice lack the Ant3 gene) [40], with a

molecular weight of ~30  kDa. The protein structure

contains 6 transmembrane α-helices [41] (Fig. 2).

As mentioned above, the involvement of ANT

in MPT pore formation was suggested in the 1970s,

and in the 1990s, understanding of the mechanism

of ANT transformation into the mitochondrial pore

was developed [14, 20, 42]. Indeed, ANT inhibitors

and substrates significantly affected Ca

capacity

and swelling of organelles [14]. When ANT was in-

corporated into giant vesicles, channel conductance

(up to 600  pS) was observed [43]. It was shown that

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oxidative modification of cysteine residues (Cys57 and

Cys160) of ANT caused formation of disulfide bridg-

es in the protein, increased mitochondrial sensitivity

to MPT pore induction through enhanced cyclophil-

in  D binding and suppressed the inhibitory effect of

ADP [44]. All this convincingly indicated the involve-

ment of ANT in MPT pore formation.

However, the results of certain experiments in

the mid-2000s almost made mitochondriologists com-

pletely abandon the idea of ANT as a part of the MPT

pore. It was shown that liver mitochondria from mice

with knockouts of the Ant1 and Ant2 genes were still

sensitive to Ca

-dependent mitochondrial swelling,

which was prevented by cyclosporin  A. Moreover,

such mitochondria had increased Ca

capacity (com-

pared to liver mitochondria from control animals),

which was reduced by the addition of oxidizing

agents, but not atractyloside (an ANT inhibitor and

MPT pore inducer) [21]. Only recently it was shown

that knockouts of all three ANT genes (Ant1, Ant2,

Ant4) in mice resulted in liver mitochondria becom-

ing virtually insensitive to Ca

ions, while the ad-

dition of cyclosporin  A or knockout of the Ppif gene

resulted in complete inhibition of the pore. Patch

clamp analysis of mitoplasts isolated from mouse em-

bryonic fibroblasts with knockouts of all three ANT

genes showed virtually no channel conductance. This

allowed to conclude that ANT is an essential compo-

nent of the MPT pore, which induces the formation

of a low-conductance pore [45].

Interestingly, increased expression of different

ANT isoforms is observed in various pathologies. For

example, in Duchenne muscular dystrophy, a decrease

in ANT1 expression and an increase in ANT2 levels

are observed in skeletal muscle cells [46]. In he-

patocytes of diabetic mice (type  1 diabetes mellitus),

a decrease in ANT1 levels was also observed [47].

On the other hand, suppression of ANT2 expression

in HEK293T cells (a cell line derived from human em-

bryonic kidneys) even enhanced the progression of

mitochondrial dysfunction under hyperlipidemic con-

ditions [48]. All this may indicate tissue-specific reg-

ulation of MPT pore activity in various pathologies.

It is believed that ANT is capable of transforming

into a channel under the influence of Ca

ions [42].

However, ANT does not have a Ca

binding site,

which suggests the effects of additional factors in

the regulation of the MPT pore (possibly cardiolip-

in) or post-translational modification [2,  49]. There

are doubts about the necessity of ANT interaction

with cyclophilin D for MPT pore formation [2,  3].

All this allows to assume that another channel

that ensures the opening of high-conductance MPT

pore can be formed in mitochondria. Surprising-

ly, a slightly incorrect interpretation of the experi-

ment conducted in the mid-2000s led to significant

progress in the search for new structural components

of the MPT pore. As a result, ATP synthase is cur-

rently considered as the key channel component of

the MPT pore.

Mitochondrial ATP synthase is one of the key mi-

tochondrial supercomplexes (~600  kDa), consisting of

a F1 complex (ATP synthesizing) and a membrane-

embedded F0. The complexes interact via a central

and a peripheral stalk. The F1 complex consists of

three pairs of αβsubunits arranged around the central

stalk (γ, δ, and γsubunits). The central stalk is linked

to the F0 complex, which consists of a lipid-filled

c-ring (integral csubunits) and an α subunit. The pe-

ripheral stalk consists of OSCP, F6, b and d subunits.

ATP synthase forms dimer rows in the inner mito-

chondrial membrane, with the key proteins being the

e, f, g, A6L, j and k subunits. These dimer rows form

the cristae structure of the inner membrane, giving

it a positive curvature [50, 51].

The possibility of ATP synthase involvement in

the formation of the mitochondrial pore was first

suggested with the discovery of a CsA-sensitive inter-

action between cyclophilin  D and OSCP (Fig.  2)  [28].

This interaction resulted in inhibition of mitochon-

drial ATP synthase activity and stimulation of MPT

pore opening. Benzodiazepine-423, a classic inhibi-

tor of ATP synthase activity, acted in a similar man-

ner, binding to OSCP at the same site as cyclophil-

in  D [23, 28].

There are currently two hypotheses on ATP syn-

thase involvement in MPT pore formation: the pore is

formed either between ATP synthase dimers or with-

in the ring of c subunits [3].

When ATP synthase was embedded in an artifi-

cial lipid membrane, a high Ca

-dependent channel

conductance (1-1.3  nS) was observed, similar to the

conductance of the MPT pore in mitoplasts [23,  52].

The conductance was observed only in the case of

the dimeric or oligomeric form of ATP synthase, but

not its monomeric form [53]. Suppression of the ex-

pression of proteins involved in the dimer formation

(subunits e, g, f) led to complete inhibition of MPT

pore opening [54-56]. Dimerization of ATP synthase

was enhanced by the ATPase inhibitor, the IF1 pro-

tein, which inhibits MPT pore opening and protects

the cell from ischemic damage [57]. All this allowed

us to assume that the MPT pore is formed in the di-

mers of ATP synthases between the e, g and f sub-

units due to their destabilization or structural rear-

rangements in each monomer [58].

On the other hand, it was shown that ATP syn-

thase monomers are also capable of forming high-con-

ductance channels [59]. When purified c  subunits

were embedded in a lipid membrane, voltage-gated

channels of varying conductance appeared in the

membrane. The conductance of most channels was

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at a level of 100  pS, but in some cases, high conduc-

tance at a level of 1.5-2  nS was also observed [60],

which is also similar to the conductance of the MPT

pore [52]. Knockdown of the c subunit of ATP syn-

thase resulted in inhibition of MPT pore opening in

mitochondria [61].

However, the possibility of the c-ring involve-

ment in MPT pore formation remains debatable. This

is due to the fact that the inner space of the ring is

filled with lipid molecules and is hydrophobic [62].

The “death fingers” hypothesis attempts to circumvent

this limitation and combine the two mechanisms de-

scribed above [63]. According to this hypothesis, the

binding of Ca

to the β  subunit of the F1 complex

of ATP synthase and the binding of cyclophilin  D to

OSCP causes a chain of conformational changes in the

 complex, which are transmitted through the pe-

ripheral stalk to the inner mitochondrial membrane

in the region of the esubunit. Simultaneous displace-

ment of the central stalk subunits and the F

complex

away from the c-ring can also occur. The e subunit

expels lipids from the c-ring lumen, which may lead

to its expansion and the emergence of channel activ-

ity. Indirect evidence for such a mechanism may be

provided by the data showing that mutations weak-

ening the c-ring packing led to an increase in the

internal diameter of the ring, an increase in chan-

nel conductance and an increase in the sensitivity of

various cells to cell death inducers [60,  64]. This hy-

pothesis describes both the reversible opening of the

pore, which can be observed under physiological and

sublethal pathological conditions, and the irreversible

opening of the pore. In the latter case, dissociation

of the F

and F

subunits may occur, which will lead

to mitochondrial swelling and cell death. However,

it should be noted that displacement of lipids from

the c-ring lumen into the hydrophilic region of the

intermembrane space is a thermodynamically unfa-

vorable process [3].

J.  Walker’s group demonstrated that knocking out

various ATP synthase proteins involved in MPT pore

formation does not suppress its activity. For exam-

ple, genetic knockout of each of the e, f, g, ksubunits

and of the 6.8  kDa proteolipid (6.8PL) disrupted the

dimerization of the complex, but the probability of

MPT pore opening did not decrease[58]. Knockout of

three nuclear genes, ATP5G1, ATP5G2, and ATP5G3,

encoding the c subunits, rendered mitochondria in

HAP1-A12 cells sensitive to MPT pore induction  [65].

Knocking down peripheral stalk proteins (β  subunits

and OSCP) either did not affect the induction of the

mitochondrial pore in cells, or ionic currents were

observed that were insensitive to cyclosporin  A, but

underwent inhibition by bongkrekic acid[54, 55]. All

this allowed us to consider ANT as a channel of the

MPT pore once again.

Recently, a consensus has emerged that adding

to mitochondria can activate the formation of

the MPT pore, whose channel in the inner membrane

can be either ANT or ATP synthase [3, 66, 67]. It has

been suggested that the opening of the pore associated

with ATP synthase occurs at physiological pH values,

while the action of ANT regulators (and, consequent-

ly, ANT-mediated pore opening) is enhanced by de-

creasing the pH from 7.4 to 6.5 [68]. In this case, the

two structures can function as an ATP synthasome.

ANT and ATP synthase embedded in an artificial lipid

membrane are able to induce channel conductivity

upon the addition of high concentrations of Ca

ions.

However, the precise molecular structure of the

mitochondrial pore remains far from being resolved.

This is due to the numerous contradictions and phe-

nomena which are difficult to explain observed in

experiments with mitochondria. This has been men-

tioned above in regards to the studies when suppres-

sion of the activity of the same genes encoding ATP

synthase proteins led to different effects in different

experiments. Meanwhile, the removal of ANT or var-

ious ATP synthase subunits leads to a decrease in

energy metabolism, suppression of respiratory activ-

ity and membrane potential generation [55, 65]. This

may be an additional factor influencing pore for-

mation in mitochondria even in the absence of cer-

tain subunits. In addition to these discrepancies, no

precise answers to questions posed several decades

ago are present yet. For example, it is still unclear

why pore induction in mitoplasts and artificial mem-

branes requires Ca

ion amounts 2-3 orders of mag-

nitude higher than in the case of intact mitochondria.

Moreover, it is still not entirely clear what the bind-

ing site for Ca

ions is [3]. Another mystery is the

ratio of the number of opening pores (up to 10) to

the number of ANT and ATP synthases (several thou-

sand copies) per mitochondrion [69, 70]. Which par-

ticular events lead to a very small number of ANT

or ATP synthases undergoing transformation and

changing their physiological function to pathological?

The answers to these questions may be one of the

cornerstones which will allow us to understand the

structure of the pore in the future.

The accessory proteins required for MPT pore

induction in mitochondria. The ability of mitochon-

drial outer membrane proteins to regulate MPT pore

opening has been known for a long time. VDAC is

a family of β-barrel proteins of the mitochondrial

outer membrane (~30-35  kDa). These are the most

abundant outer membrane proteins that regulate the

transport of metabolites and ions from cytoplasm to

mitochondria. VDAC has long been considered one of

the main components of the MPT pore, since the con-

ductance of VDAC channels is similar to that of the

MPT pore (Fig.  2) [71]. It was believed that the pore

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BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

is formed in the contact site region where the

connection of outer and inner mitochondrial mem-

branes occurs. However, in isolated mitochondria,

VDAC is not required for MPT pore formation [5].

Thus, mitochondrial pore opening can be induced in

mitoplasts and submitochondrial particles [72,  73].

Furthermore, pore opening occurs in mitochondria

isolated from mice in which all three VDAC isoforms

were knocked out [74]. However, the role of VDAC

in MPT pore formation in a living cell should not

be underestimated, since these channels provide the

main pathway for Ca

ions influx into mitochon-

dria. Various cytoplasmic protein kinases (e.g., GSK3β,

PKA (protein kinase  A), etc.) lower the threshold for

MPT pore opening to various inducers by phosphor-

ylating VDAC [71].

TSPO is another protein (18  kDa) localized in the

outer mitochondrial membrane[75], for which partic-

ipation in MPT pore formation has been described.

TSPO is involved in the regulation of many meta-

bolic processes, the key one of which is cholesterol

transport into mitochondria [76,  77]. It was believed

that this protein facilitates the formation of the con-

tact site between VDAC and ANT [77]. Meanwhile, in

rat brain mitochondria, cholesterol binding to TSPO

resulted in suppression of cyclosporin A-insensitive

membrane potential decrease and Ca

release from

mitochondria [78]. Antibodies against TSPO caused

an increase in Ca

capacity of mitochondria [78,  79].

A number of TSPO ligands caused MPT pore activa-

tion [76]. At the same time, there is evidence that

suppression of TSPO expression in animal tissues did

not cause a significant change in MPT pore induc-

tion [79]. Therefore, the role of TSPO in MPT pore

formation cannot be considered proven yet, and the

stimulating effects of ligands may be associated with

the presence of other mitochondrial targets in the

latter [23].

The involvement of other proteins of the out-

er mitochondrial membrane (in particular, proteins

of the Bcl2 family) in MPT pore regulation has also

been shown [5]. It has been suggested that the Bax

and Bid proteins stimulate the pore opening in mi-

tochondria, since their genetic knockout leads to in-

hibition of MPT-induced mitochondrial swelling and

cell death[80]. However, it should be noted that these

proteins induce the formation of large pores in the

outer mitochondrial membrane primarily as a result

of oligomerization with each other or with VDAC[71].

This can surely promote MPT pore opening, but

it rather appears to be a parallel process.

As mentioned above, in the mid-2000s, a phos-

phate transporter capable of interacting with cyclo-

philin D was considered as a possible structural unit

of the MPT pore in the inner membrane [22]. Today,

it is believed that even if the phosphate transporter is

involved in pore formation, its expression level does

not limit the process of MPT pore opening[81]. It can

be assumed that, being part of the ATP synthasome,

this transporter may be indirectly involved in pore

induction mediated by ANT or ATP synthase[2]. Other

proteins (aldehyde dehydrogenase (Aldh6a1 gene)

and prohibitin 2) associated with ATP synthase can

also modulate ATP synthase-mediated MPT pore [82].

A 2015 study showed that, in addition to cyclo-

philin  D, spastic paraplegia 7 (SPG7) is also an es-

sential component [83]. This is a protein of the AAA

protease family, localized in the inner mitochondri-

al membrane. Genetic knockout of SPG7 resulted in

suppression of MPT pore opening in mitochondria

induced by Ca

or oxidative stress and also prevent-

ed cell death. There are several possible explanations

for SPG7 involvement in MPT pore induction, rang-

ing from its effect on mitochondrial Ca

transport

to suppression of SIRT3 (sirtuin  3) expression and, a

consequently, suppression of cyclophilin  D deacetyla-

tion [84, 85]. Other studies found that increasing or

decreasing SPG7 expression by using siRNA did not

affect MPT pore induction in mitochondria [86]. All

these facts allow us to say that SPG7 may indirectly

participate in the induction of the MPT pore, but it is

not an essential component of the pore.

Another group of enzymes involved in MPT pore

regulation are various kinases, including mitochon-

drial creatine kinase, hexokinase, and GSK-3β[87-89].

Their ability to regulate the pore is believed to be

associated primarily with their interaction with VDAC

and ANT. Thus, increased expression of creatine ki-

nase and hexokinase suppresses MPT pore opening

and prevents the development of cell death  [49].

Due to this, one of the cancer cell markers is over-

expression of mitochondria-associated hexokinases  I

and II [90]. Kinases can interact with VDAC either

directly (the hydrophobic N-terminus of hexokinase

interacts with Glu73 of VDAC, preventing its oligo-

merization) or through Ser and Thr residue phos-

phorylation (inhibition or phosphorylation of GSK-3β

prevents mitochondrial ROS production, MPT pore

induction and cell death) [71, 89].

Alternative mechanisms of mitochondrial pore

induction which are insensitive to cyclosporin  A.

The possibility of inhibiting mitochondrial pore for-

mation by cyclosporinA allowed researchers to focus

their attention on the MPT pore phenomenon. Thus,

studies of the role of the mitochondrial pore in var-

ious diseases are often determined by the effect of

CsA or other MPT inhibitors on the process. Howev-

er, it is possible to induce non-specific mitochondrial

permeability that is insensitive to cyclosporin  A. This

suggests that regulation of such permeability is not

associated with cyclophilin  D. Exogenous amphipathic

peptides (e.g., signaling proteins), certain prooxidants,

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hormones (thyroxine) and fatty acids have the ability

to induce Ca

-dependent permeability of the inner

mitochondrial membrane that is insensitive to cyclo-

sporin [12, 91].

The possibility of inducing a Ca

-dependent pore

mediated by fatty acids and phospholipase A

activ-

ity was established quite a long time ago [11-13, 92,

93]. The insensitivity of this phenomenon to CsA was

demonstrated in the early 2000s: saturated palmitic

acid in the presence of Ca

ions induced swelling

of mitochondria isolated from various tissues. At the

same time, it was shown that palmitic acid similar-

ly induces Ca

-dependent permeabilization of both

natural (mitochondrial and erythrocyte plasma mem-

branes) and artificial lipid membranes (unilamellar li-

posomes and bilayer lipid membranes)[13]. Based on

these and a number of other characteristics, we con-

cluded that the pore induced by saturated fatty acids

and Ca

is of lipid origin[93]. It was shown that the

mechanism of palmitate/Ca

-induced pore formation

is based on the ability of saturated fatty acid anions

to form strong complexes with Ca

in the lipid bilay-

er, followed by their separation into solid crystalline

membrane domains and the appearance of hydro-

philic lipid pores[12,93]. Importantly, lipid pores are

characterized by their self-sealing ability, which may

be of physiological significance for the mechanism of

mitochondrial Ca

unloading [13]. The formation of

such pores in a living cell can occur due to phos-

pholipase  A

activation [13,  94]. More details on the

lipid pore induced by palmitic acid and Ca

can be

found in the review by Mironova and Pavlov [13].

MPT PORE INHIBITORS

IN MITOCHONDRIA

Understanding the mechanisms of MPT pore ac-

tivation and its involvement in pathological processes

naturally leads us to the question of the possibilities

of modulating this pore’s function. One of the most

detailed analyses of MPT pore modulators was giv-

en in the review by Zoratti and Szabo [1] in 1995.

Today, the development of MPT pore inhibitors has

entered the phase of targeted design: using structural

modeling, high-throughput screening and analysis of

interactions with both the regulators of its opening

(cyclophilin  D, TSPO) and the discussed direct com-

ponents of the pore (such as ANT and ATP synthase).

The most studied MPT pore inhibitor is cyclo-

sporin  A [17-19]. Its discovery not only confirmed

the role of the MPT pore in cell death but also pro-

vided a direction for further research. However, the

use of CsA as a cardio- or neuroprotector is limit-

ed by its side effects, including immunosuppression,

nephrotoxicity and its lack of selectivity regarding

other cyclophilins. Furthermore, its low permeabili-

ty across the blood-brain barrier limits its potential

use against neurological diseases [95]. Other natural

cyclosporins B, C, D, and E have also been studied

for their ability to modulate MPT pore opening. They

differ by minor variations in amino acid sequences,

which, however, have a significant impact on their

activity. For example, cyclosporins A, B, C, and D ex-

hibit significant conformational dynamics, whereas

cyclosporin  E, being more rigid due to the absence

of a methyl group at Val11 position, loses the ability

to inhibit MPT pore opening [96].

One of the ways to enhance the selective prop-

erties of cyclosporin A was elimination of immu-

nosuppressive activity. Thus, in 1994, a cyclosporin

derivative, N-methyl-4-isoleucine-cyclosporin (NIM811

or GNX-4975)  [1,  97], was obtained. It retained high

affinity for cyclophilin  D but did not suppress cal-

cineurin, which deprived it of immunomodulatory

activity and could potentially expand its therapeutic

window. This allowed NIM811 to reach the stage of

preclinical and early clinical trials against myocar-

dial infarction and stroke. Another promising com-

pound lacking any immunosuppressive properties

is alisporivir (Debio 025), which has shown higher

selectivity for cyclophilin  D, having successfully per-

formed in models of diabetes, Duchenne muscular

dystrophy [98,  99], collagenopathy [100], Alzheimer’s

disease [101] and having passed clinical trials for

hepatitis  C. However, like cyclosporin  A, alisporivir

exhibited non-selective effects on mitochondrial bio-

energetics (already at micromolar concentrations,

which are classical for in  vitro experiments), which

is due to its hydrophobic nature and the ability to

accumulate in the lipid phase of membranes and af-

fect their physical properties [102].

Cyclophilin  D is not the only regulatory molecule

through which MPT pore status is modulated. The

involvement of TSPO in pore opening and its modu-

lation by the synthetic agent TRO40303, which is ca-

pable of preventing pathological opening of the MPT

pore, is being discussed [103].

In addition to cyclosporins, the natural macrolide

compound sanglifehrin A, isolated from actinomy-

cetes, is among the classic MPT pore inhibitors. San-

glifehrin  A is capable of binding to cyclophilin  D, but

at a different site than cyclosporin  A, and does not

inhibit calcineurin. Furthermore, unlike CsA, sangli-

fehrin  A does not affect the binding of cyclophilin  D

to ANT [104]. In experiments on cardiac tissue, san-

glifehrinA reduced myocardial damage during reper-

fusion, decreasing infarction size and protecting cells

from oxidative stress if the compound was adminis-

tered during the first minutes of reperfusion [105].

However, like CsA, sanglifehrin  A also has immuno-

suppressive properties, which limits its use. Another

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BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

example is bongkrekic acid, produced by Burkholde-

ria gladioli pathovar cocovenenans bacteria. It blocks

MPT pore opening binding to ANT. However, its high

toxicity limits its clinical applications.

In addition to well-known ANT modulators ca-

pable of inhibiting MPT pore opening, agents capa-

ble of influencing the pore-forming activity of ATP

synthase are currently being developed. For exam-

ple, a new class of MPT pore inhibitors based on

1,4,8-triazaspiro[4.5]decan-2-one has recently been

presented [106]. The most promising compound, 14e,

demonstrated high inhibitory activity at micromolar

concentrations and a pronounced cytoprotective ef-

fect in a model of cardiomyocyte hypoxia/reoxygen-

ation. The effect is apparently due to the influence of

the compounds on ATP synthase which is a structural

component of the MPT pore. Molecular modeling re-

vealed a potential binding site for the compounds at

the junction of the c-ring and the a subunit of ATP

synthase, and in this case, the structural features of

14e provided the greatest affinity for this site [106].

High-throughput screening also identified efficient

MPT pore inhibitors among cinnamyl anilides, isoxaz-

oles and benzamides [107-110]. These compounds are

more potent than cyclosporin  A and exhibit marked

specificity, acting independently of cyclophilin  D.

However, these compounds are characterized by low

metabolic stability (e.g., isoxazoles) and, in some cas-

es (benzamides), toxicity, meaning that further opti-

mization of their structure is required.

It should be noted that pore inhibitors are be-

ing actively developed for at least two main rea-

sons: the emergence of new scientific hypotheses

about the pore structure and the identification of the

role of the mitochondrial pore in the development

of pathologies.

THE ROLE OF MPT PORES

IN THE DEVELOPMENT

OF CELLULAR PATHOLOGIES

The first papers suggesting the involvement of

the MPT pore in the development of cellular pathol-

ogies appeared in the late 1970s, when it was discov-

ered that a sharp increase in the permeability of the

inner mitochondrial membrane can be triggered by

overload and oxidative stress and is closely as-

sociated with cell death. At that time, it was already

shown that MPT pore opening leads to mitochondrial

swelling, rupture of outer mitochondrial membrane

and activation of apoptosis or necrosis, which was

believed to be associated with tissue damage during

cardiac ischemia/reperfusion and other acute condi-

tions. In the following decades, research confirmed

the key role of the MPT pore in the pathogenesis of

awide range of diseases, including neurodegenerative

and neuromuscular diseases, cardiovascular diseases,

diabetes, bone remodeling pathologies and cancer

(Fig. 3). Although the molecular structure of the pore

is still under debate, its involvement in pathologies is

widely accepted, and modulation of its activity is con-

sidered a promising therapeutic strategy [111]. More-

over, accumulated data suggest that the occurrence

of pathologies associated with the process of aging,

primarily neurodegenerative disorders, metabolic and

cardiovascular pathologies, is also due to an age-relat-

ed increase in cell sensitivity to MPT pore induction.

Indeed, indirect measurements show that the MPT

pore is activated more efficiently in tissues of old

organisms, especially when exposed to high concen-

trations of Ca

and inorganic phosphate ions [112].

In addition, experiments on model organisms such as

Caenorhabditis elegans demonstrate that stimulation

of MPT pore induction shortens lifespan, while its in-

hibition can have a protective effect [113]. However,

the mechanisms that determine the transition from

the physiological to the pathological role of the MPT

pore remain not fully understood.

Participation of the MPT pore in the pathogen-

esis of neurodegenerative diseases. The MPT pore

plays a key role in the development of neurodegen-

erative diseases such as Alzheimer’s and Parkinson’s

diseases, amyotrophic lateral sclerosis (ALS), as well

as in the processes of axonal degeneration and neu-

ronal death. It is believed that MPT pore induction in

Alzheimer’s and Parkinson’s diseases is caused by ac-

cumulation of aggregates of pathological proteins in

nerve cells, such as β-amyloid, tau protein and α-sy-

nuclein, which are able to interact with MPT pore

components (e.g., cyclophilin D, VDAC, ANT, and ATP

synthase) [7, 114-116]. Experimental models of ALS

(G93A-mSOD1 mice) revealed structural rearrange-

ments of motor neuron mitochondria, accompanied

by an increase in the number of contacts between the

inner and outer membranes, which is believed to con-

tribute to the induction of the MPT pore [116]. Since

such mitochondria cease to produce ATP efficiently,

cells with high energy demands (e.g., dopaminergic

neurons in Parkinson’s disease or motor neurons in

ALS) begin to experience energy deficiency, which

leads to their degeneration. Furthermore, mitochon-

drial dysfunction promotes increased ROS formation

and development of oxidative stress. Opening of the

MPT pore promotes the release of cytochrome  c and

other proinflammatory molecules, such as mitochon-

drial DNA, which increases neuroinflammation and

further contributes to nerve tissue damage [7]. More-

over, mitochondrial sensitivity to MPT pore opening

increases with age. This is associated with impaired

calcium homeostasis, increased oxidative stress and

changes in the composition of mitochondrial proteins,

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BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

Fig. 3. A scheme illustrating MPT pore participation in the development of various pathological processes. Explanations are

given in the text. ANT, adenine nucleotide translocator; VDAC, voltage-dependent anion channel of the outer mitochondrial

membrane. The image was created by using BioRender.

which may explain the age-related vulnerability of the

brain to neurodegeneration [7]. These effects can be

eliminated by pharmacological inhibition of the MPT

pore with cyclosporin A [117] and olesoxime [118].

Participation of the MPT pore in the devel-

opment of pathologies caused by tissue ischemia/

reperfusion. The role of the MPT pore in damage

caused in tissues highly sensitive to hypoxia and subse-

quent reoxygenation (heart, brain, kidneys) is current-

ly being actively discussed [3,  4]. Specifically, during

myocardial infarction, which occurs due to ischemic

damage to the heart muscle, Ca

ions and inorgan-

ic phosphate accumulate in cardiomyocytes, creating

preconditions for MPT pore induction in mitochon-

dria. However, in the initial period of pathology de-

velopment, low intracellular pH and high ADP levels

temporarily suppress pore opening, delaying the on-

set of consequences. The situation changes drastical-

ly under reperfusion conditions, when restoration of

blood flow leads to normalization of pH values and

the “washout” of inhibitory factors, creating favor-

able conditions for MPT pore formation. It is also

important to note that, in addition to the classical

-dependent mechanism, oxidative stress plays a

significant role in regulating MPT pore formation in

mitochondria in cardiovascular pathologies. For ex-

ample, accumulation of intracellular succinate during

ischemia can lead to increased ROS formation as a

result of reverse electron transfer in the mitochondri-

al respiratory chain during subsequent reperfusion,

which further facilitates MPT pore opening in organ-

elles [4]. Subsequently, pore induction under such

conditions causes a collapse of mitochondrial mem-

brane potential, swelling and destruction of mito-

chondria, which triggers a cascade of events leading

to necrosis of cardiomyocytes and other types of cells

in the myocardium. This process is directly related to

the localization and volume of the infarction zone:

the more mitochondria undergo MPT pore induction,

the larger the area of necrotic tissue. Experimental

models convincingly demonstrate that preventing

MPT pore formation with cyclosporin  A, using cyclo-

philin  D gene knockout methods or initiating the isch-

emic preconditioning effect significantly reduce tis-

sue damage during ischemia/reperfusion [119, 120].

However, clinical studies based on pharmacological

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BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

inhibition of the MPT pore in patients with myocardi-

al infarction have shown conflicting results [121], in-

dicating the need to optimize therapeutic approaches.

MPT pore involvement in neuromuscular dis-

eases. The idea of mitochondrial dysfunction being

involved in the pathogenesis of neuromuscular dis-

eases was proposed for the first time almost 50years

ago [122]. Currently, the main focus is on how MPT

pore induction caused by Ca

overload and oxida-

tive stress in dysfunctional mitochondria leads to

muscle fiber damage and death. It has been found

that the MPT pore may play an important role in

the development of muscular dystrophies associated

with deficiency of collagen  VI (e.g., Bethlem myopa-

thy, Ullrich congenital muscular dystrophy, myoscle-

rosis), dystrophin (Duchenne and Becker muscular

dystrophy), δ-sarcoglycan (limb-girdle muscular dys-

trophy), and laminin [123, 124]. In all these cases, the

absence of structural proteins leads to a disruption of

the stability of muscle fiber sarcolemma (both its in-

tegrity and the function of ion channels and signaling

molecules) and an excessive influx of calcium ions

from the extracellular space [125]. Excessive calcium

uptake by mitochondria under these conditions com-

bined with oxidative stress makes them extremely

sensitive to MPT pore opening and triggers a cascade

of pathological events, from the loss of mitochondri-

al membrane potential to the release of proapoptot-

ic factors and, ultimately, muscle fiber death [46].

In addition, mitochondria overloaded with calci-

um phosphate can act as foci of tissue calcification,

thereby promoting tissue degeneration [126]. It is in-

teresting to note that mitochondria in the hearts of

dystrophic mdx mice (a model of Duchenne muscular

dystrophy) exhibit resistance to MPT pore induction,

which may be linked to tissue-specific expression of

proteins associated with its formation and regulation

(cyclophilin  D, ANT, ATP synthase subunits)[127]. This

is supposed to contribute to the delayed development

of cardiac pathologies, which is characteristic of both

model animals and patients. Meanwhile, MPT pore in-

hibitors (CsA, alisporivir, NIM) are able to slow the

development of muscle pathology in model animals

and also improve the condition of skeletal muscles in

patients[98, 99, 110,124]. A similar effect is achieved

by blocking mitochondrial calcium overload with in-

hibitors of Ca

-transporting proteins[125]. A number

of pharmacological inhibitors are currently in early

clinical trials. Recent studies involving inactivation of

genes of cyclophilin  D and ANT, the presumed pro-

tein components of the pore, also confirm the role of

the MPT pore in the development of muscle pathol-

ogies [124, 128].

It has been shown that the MPT pore may be

involved in pathogenesis of multisystem diseases, in-

cluding those affecting muscle tissue. Early stages of

ALS are characterized by disrupted calcium homeosta-

sis and oxidative stress in the brain, spinal cord, and

skeletal muscles, which contributes to increased sus-

ceptibility of mitochondria in the cells of these tissues

to MPT pore opening [129]. The involvement of the

MPT pore formation in age-related muscle degenera-

tion has also been described [130]. The lack of effec-

tive therapy for these pathologies, which are in most

cases sporadic and multifactorial, allows us to consid-

er the MPT pore as one of the promising pharmaco-

logical targets. Further research in this area may also

contribute to improving the diagnostic approaches to

most neuromuscular pathologies accompanied by mi-

tochondrial dysfunction already in the early stages.

The role of the MPT pore in the development

of diabetes mellitus. In type  1 and type  2 diabetes

mellitus, hyperglycemia, hyperlipidemia, and oxida-

tive stress increase mitochondrial sensitivity to MPT

pore opening in most tissues, which leads to a loss

of membrane potential, increased ROS production

and the release of proapoptotic factors [131]. Patho-

logical induction of the MPT pore in diabetes has

been described for pancreatic β-cells [132], cardio-

myocytes [133] and neurons [134]. The involvement

of this phenomenon in diabetic complications, such

as cardiomyopathy, is also being discussed. Mean-

while, sensitivity to MPT pore opening in diabetes

varies depending on the tissue type. For example,

mitochondria of the heart and skeletal muscles be-

come more susceptible to the opening of the pore in

diabetes, which increases oxidative stress and cell

damage [135, 136]. At the same time, an increase in

resistance to MPT pore induction is observed in the

liver, which may also be associated with tissue-spe-

cific expression of pore proteins and is considered

an adaptive mechanism which prevents acute toxic

organ damage [137]. Interestingly, this significantly

distinguishes the pathology of diabetes from other

metabolic diseases, such as non-alcoholic fatty liv-

er disease, which is characterized by accumulation

of free fatty acids in hepatocytes and the develop-

ment of lipotoxicity, which contributes to the disrup-

tion of the respiratory chain, increased ROS forma-

tion and a significant increase in the sensitivity of

liver cells to MPT pore induction [138]. It has been

shown that both genetic and pharmacological inhibi-

tion of the MPT pore by using cyclophilinD blockers

(CsA and alisporivir) can protect against mitochon-

drial damage caused by diabetes or other metabol-

ic pathologies, improve glucose utilization and re-

duce oxidative stress, thereby alleviating cardiac

and skeletal muscle dysfunction [131, 133, 139-141].

We have shown that blockers of VDAC (VBIT-4) and

ANT(bongkrekic acid), potential channel components

of the MPT pore, exhibit a cytoprotective effect under

these conditions [48, 142].

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BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

Fig. 4. Number of publications by year in the PubMed database in response to the query “Mitochondrial Permeability

Transition”. https://pubmed.ncbi.nlm.nih.gov/?term=mitochondrial+permeability+transition&sort=date.

It should be noted that diabetes mellitus is a

chronic disease. In this regard, mitochondrial pore in-

duction in a high-conductivity state may be a feature

of such extremely pathological manifestations as dia-

betic foot syndrome. In all other cases, however, MPT

pore activation occurs in a low-conductivity “flicker-

ing” state which rather represents a mechanism of

adaptation to mitochondrial calcium overload.

MPT pore participation in bone remodeling

pathologies. Recent data indicate that the MPT pore

is involved in the regulation of bone cell metabolism,

including mesenchymal stem cells, osteoblasts and os-

teoclasts [143]. In mesenchymal stem cells, decreased

MPT pore opening activity promotes osteogenic dif-

ferentiation, which is associated with the suppression

of cyclophilin  D expression via the BMP/Smad signal-

ing pathway [144].

Pathological opening of the MPT pore is observed

in age-related osteoporosis, which is accompanied by

a decrease in bone mass and impaired mitochondri-

al function. Knockdown of cyclophilin  D or its phar-

macological inhibition (e.g., by using NIM811) im-

proves bone health in aged mice, preventing loss of

bone mass [145]. Osteoporosis induced by excessive

glucocorticoid (e.g., dexamethasone) intake has also

been shown to be associated with MPT pore activa-

tion, which promotes osteoblast apoptosis. This effect,

observed in gum tissue, is believed to be due to an

increase in cyclophilin  D levels in tissues and is re-

moved by cyclosporin  A or knockdown of this pore

protein [146].

In models of periodontitis and osteoarthritis, ex-

cessive induction of the MPT pore facilitates activa-

tion of inflammatory pathways and bone resorption.

Meanwhile, MPT pore inhibition reduces the intensity

of inflammation and bone tissue loss [147].

MPT pore and oncological diseases. Unlike

other pathologies discussed above, in which the MPT

pore acts as an unambiguous driver of cell, tissue,

and organ damage, its activity in carcinogenesis is

subject to complex regulation, reflecting tumor cell

adaptation to stress. The Warburg effect, which is

characteristic of many tumors and involves increased

glycolysis in cells even in the presence of oxygen,

creates a unique metabolic background (cytoplasmic

acidosis and decreased inorganic phosphate levels)

that helps to block MPT pore induction [148]. Fur-

thermore, oncogenic signaling pathways (e.g., Bcl-2

family proteins, Akt or mutant p53) actively suppress

the pore’s sensitivity to calcium and oxidative stress.

This allows malignant cells to maintain viability even

under conditions that would inevitably lead to mito-

chondria-mediated death in normal tissues [4].

Expression of many MPT pore components is sig-

nificantly increased in tumor cells[71]. It is suggested

that this may provide cancer cells with the capabil-

ity of fine regulation, ranging from complete sup-

pression of MPT pore formation (for cell survival) to

its controlled activation (for adaptation to changing

microenvironmental conditions). This may underlie

the heterogeneity of many tumor types and explain

their resistance to therapy. Nevertheless, a number

of approaches involving the use of oxidative stress

inducers and calcium homeostasis modulators may

be used to combat tumors, provided that the issue of

their selectivity is addressed [4].

Is it possible to accurately decipher the structure

of the MPT pore, determine the molecular mechanism

of its formation and visualize this phenomenon in a

living cell? It should be acknowledged that the pros-

pects, given current capabilities and experimental ap-

proaches, as well as the known limitations (including

BELOSLUDTSEV et al.1802

BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

the rarity of this event in mitochondria), are not very

promising. This is indirectly evidenced by the trend in

publications: despite the recognized role of the MPT

pore in the development of cellular pathologies and

socially significant diseases, as well as active research

in this area, the number of articles has been grad-

ually decreasing since 2015 (Fig.  4). The emergence

of new methodological approaches and selective in-

hibitors could not only allow to establish the precise

structure of the pore complex but also to provide a

new direction for therapy and diagnosing various cel-

lular pathologies associated with MPT pore induction

and associated organelle dysfunction.

Abbreviations

ANT adenine nucleotide translocator

CsA cyclosporinA

MPT

mitochondrial permeability transition

pore

OSCP

oligomycin sensitivity conferring pro-

tein

ROS reactive oxygen species

SPG7 spastic paraplegia 7

TSPO peripheral benzodiazepine receptor

VDAC voltage-dependent anion channel

Contributions

K. N. Belosludtsev – concept; N. V. Belosludtseva,

M. V. Dubinin, and K. N. Belosludtsev – writing the

manuscript; N. V. Belosludtseva and K. N. Beloslud-

tsev – editing the manuscript; M. V. Dubinin and

K. N. Belosludtsev– creating the figures.

Funding

The work was carried out with the support of the Rus-

sian Science Foundation (grant no.25-65-00005).

Ethics approval and consent to participate

This work does not contain any studies involving

human and animal subjects.

Conflict of interest

The authors of this work declare that they have

noconflicts of interest.

REFERENCES

1. Zoratti,M., and Szabo,I. (1995) Mitochondrial perme-

ability transition, Biochim. Biophys. Acta, 1241, 139-

176, https://doi.org/10.1016/0304-4157(95)00003-A.

2. Frigo, E., Tommasin, L., Lippe, G., Carraro, M., and

Bernardi, P. (2023) The haves and have-nots: the

mitochondrial permeability transition pore across

species, Cells, 12, 1409, https://doi.org/10.3390/

cells12101409.

3. Bernardi, P., Gerle, C., Halestrap, A. P., Jonas, E. A.,

Karch,J., Mnatsakanyan,N., Pavlov,E., Sheu, S.S., and

Soukas, A. A. (2023) Identity, structure, and function

of the mitochondrial permeability transition pore:

controversies, consensus, recent advances, and future

directions, Cell Death Differ., 30, 1869-1885, https://

doi.org/10.1038/s41418-023-01187-0.

4. Bonora,M., Patergnani,S., Ramaccini,D., Morciano,G.,

Pedriali, G., Kahsay, A. E., Bouhamida, E., Giorgi, C.,

Wieckowski, M.R., and Pinton,P. (2020) Physiopathol-

ogy of the permeability transition pore: molecular

mechanisms in human pathology, Biomolecules, 10,

998, https://doi.org/10.3390/biom10070998.

5. Halestrap, A.P., and Richardson, A.P. (2015) Themi-

tochondrial permeability transition: a current per-

spective on its identity and role in ischaemia/reper-

fusion injury, J.Mol. Cell. Cardiol., 78, 129-141, https://

doi.org/10.1016/j.yjmcc.2014.08.018.

6. Carraro, M., and Bernardi, P. (2023) The mitochon-

drial permeability transition pore in Ca

homeosta-

sis, Cell Calcium, 111, 102719, https://doi.org/10.1016/

j.ceca.2023.102719.

7. Baev, A.Y., Vinokurov, A.Y., Potapova, E. V., Dunaev,

A.V., Angelova, P.R., and Abramov, A.Y. (2024) Mito-

chondrial permeability transition, cell death and neu-

rodegeneration, Cells, 13, 648, https://doi.org/10.3390/

cells13070648.

8. Raaflaub, J. (1953) Swelling of isolated mitochondria

of the liver and their susceptibility to physicochem-

ical influences, Helv. Physiol. Pharmacol. Acta, 11,

142-156.

9. Lehninger, A. L. (1959) Reversal of various types of

mitochondrial swelling by adenosine triphosphate,

J.Biol. Chem., 234, 2465-2471, https://doi.org/10.1016/

S0021-9258(18)69836-9.

10. Waite,M., Van Deenen, L., Ruigrok,T., and Elbers, P.

(1969) Relation of mitochondrial phospholipase A

activity to mitochondrial swelling, J.Lipid Res.,

10, 599-608, https://doi.org/10.1016/S0022-2275(20)

43055-X.

11. Broekemeier, K.M., Schmid, P. C., Schmid, H.H., and

Pfeiffer, D. R. (1985) Effects of phospholipase A2 in-

hibitors on ruthenium red-induced Ca

release from

mitochondria, J. Biol. Chem., 260, 105-113, https://

doi.org/10.1016/S0021-9258(18)89700-9.

12. Belosludtsev, K. N., Dubinin, M. V., Belosludtseva,

N. V., and Mironova, G. D. (2019) Mitochondrial Ca

transport: mechanisms, molecular structures, and

role in cells, Biochemistry (Moscow), 84, 593-607,

https://doi.org/10.1134/S0006297919060026.

13. Mironova, G.D., and Pavlov, E.V. (2021) Mitochondri-

al cyclosporine A-independent palmitate/Ca

-induced

permeability transition pore (PA-mPT Pore) and its

role in mitochondrial function and protection against

calcium overload and glutamate toxicity, Cells, 10,

125, https://doi.org/10.3390/cells10010125.

MPT PORE: STRUCTURE AND FUNCTIONS 1803

BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

14. Hunter, D.R., and Haworth, R. A. (1979) TheCa

-in-

duced membrane transition in mitochondria.

I. The protective mechanisms, Arch. Biochem. Bio-

phys., 195, 453-459, https://doi.org/10.1016/0003-

9861(79)90371-0.

15. Haworth, R. A., and Hunter, D. R. (1979) TheCa

-in-

duced membrane transition in mitochondria. II. Na-

ture of the Ca

trigger site, Arch Biochem Biophys.,

195, 460-467, https://doi.org/10.1016/0003-9861(79)

90372-2.

16. Hunter, D.R., and Haworth, R. A. (1979) TheCa

-in-

duced membrane transition in mitochondria. III.Tran-

sitional Ca

release, Arch Biochem Biophys., 195,

468-477, https://doi.org/10.1016/0003-9861(79)90373-4.

17. Crompton, M., Ellinger, H., and Costi, A. (1988) Inhi-

bition by cyclosporin A of a Ca

-dependent pore in

heart mitochondria activated by inorganic phosphate

and oxidative stress, Biochem.J., 255, 357-360.

18. Fournier,N., Ducet,G., and Crevat,A. (1987) Action of

cyclosporine on mitochondrial calcium fluxes, J.Bio-

energ. Biomembr., 19, 297-303, https://doi.org/10.1007/

BF00762419.

19. Coluccino,G., Muraca, V.P., Corazza,A., and Lippe,G.

(2023) Cyclophilin D in mitochondrial dysfunction:

a key player in neurodegeneration? Biomolecules,

13, 1265, https://doi.org/10.3390/biom13081265.

20. Halestrap, A. P., and Davidson, A. M. (1990) Inhibi-

tion of Ca

-induced large-amplitude swelling of liver

and heart mitochondria by cyclosporin is probably

caused by the inhibitor binding to mitochondrial-ma-

trix peptidyl-prolyl cis-trans isomerase and prevent-

ing it interacting with the adenine nucleotide translo-

case, Biochem.J., 268, 153-160, https://doi.org/10.1042/

bj2680153.

21. Kokoszka, J., Waymire, K., Levy, S., Sligh, J., Gai, J.,

Jones, D., MacGregor, G., and Wallace, D. (2004)

The ADP/ATP translocator is not essential for the

mitochondrial permeability transition pore, Nature,

427, 461-465, https://doi.org/10.1038/nature02229.

22. Leung, A.W., Varanyuwatana,P., and Halestrap, A.P.

(2008) Themitochondrial phosphate carrier interacts

with cyclophilinD and may play a key role in the per-

meability transition, J.Biol. Chem., 283, 26312-26323,

https://doi.org/10.1074/jbc.M805235200.

23. Giorgio,V., von Stockum,S., Antoniel,M., Fabbro,A.,

Fogolari, F., Forte, M., Glick, G. D., Petronilli, V.,

Zoratti, M., Szabo, I., Lippe, G., and Bernardi, P.

(2013) Dimers of mitochondrial ATP synthase form

the permeability transition pore, Proc. Natl. Acad.

Sci. USA, 110, 5887-5892, https://doi.org/10.1073/pnas.

1217823110.

24. Mnatsakanyan,N., Beutner, G., Porter, G. A., Alavian,

K. N., and Jonas, E. A. (2017) Physiological roles of

the mitochondrial permeability transition pore, J.Bio-

energ. Biomembr., 49, 13-25, https://doi.org/10.1007/

s10863-016-9652-1.

25. Mithal, D. S., and Chandel, N. S. (2020) Mitochon-

drial dysfunction in fragile-X syndrome: plugging

the leak may save the ship, Mol Cell., 80, 381-383,

https://doi.org/10.1016/j.molcel.2020.10.002.

26. Galat, A. (1993) Peptidylproline cis-trans-isomeras-

es: immunophilins, Eur. J. Biochem., 216, 689-707,

https://doi.org/10.1111/j.1432-1033.1993.tb18189.x.

27. Porter, G. A., Jr., and Beutner, G. (2018) Cyclophil-

in D, somehow a master regulator of mitochondrial

function, Biomolecules, 8, 176, https://doi.org/10.3390/

biom8040176.

28. Giorgio,V., Bisetto,E., Soriano, M.E., Dabbeni-Sala,F.,

Basso,E., Petronilli,V., Forte, M.A., Bernardi, P., and

Lippe, G. (2009) Cyclophilin D modulates mitochon-

drial F

-ATP synthase by interacting with the lateral

stalk of the complex, J.Biol. Chem., 284, 33982-33988,

https://doi.org/10.1074/jbc.M109.020115.

29. Crompton, M., Virji, S., and Ward, J. M. (1988) Cy-

clophilin-D binds strongly to complexes of the volt-

age-dependent anion channel and the adenine nucle-

otide translocase to form the permeability transition

pore, Eur. J. Biochem., 258, 729-735, https://doi.org/

10.1046/j.1432-1327.1998.2580729.x.

30. Baines, C. P., Kaiser, R. A., Purcell, N. H., Blair, N. S.,

Osinska, H., Hambleton, M. A., Brunskill, E. W.,

Sayen, M.R., Gottlieb, R. A., Dorn, G. W., Robbins, J.,

and Molkentin, J. D. (2005) Loss of cyclophilin D

reveals a critical role for mitochondrial permea-

bility transition in cell death, Nature, 434, 658-662,

https://doi.org/10.1038/nature03434.

31. Scorrano, L., Nicolli, A., Basso, E., Petronilli, V., and

Bernardi, P. (1997) Two modes of activation of the

permeability transition pore: the role of mitochon-

drial cyclophilin, Mol. Cell Biochem., 174, 181-184,

https://doi.org/10.1007/978-1-4615-6111-8_27.

32. Beutner, G., Alanzalon, R. E., and Porter, G. A., Jr.

(2017) Cyclophilin D regulates the dynamic assem-

bly of mitochondrial ATP synthase into synthasomes,

Sci. Rep., 7, 14488, https://doi.org/10.1038/s41598-017-

14795-x.

33. Castillo, E. C., Morales, J. A., Chapoy-Villanueva, H.,

Silva-Platas,C., Treviño-Saldaña,N., Guerrero- Beltrán,

C. E., Bernal-Ramírez, J., Torres-Quintanilla, A.,

García, N., Youker, K., Torre-Amione, G., and García-

Rivas, G. (2019) Mitochondrial hyperacetylation in

the failing hearts of obese patients mediated partly

by a reduction in SIRT3: the involvement of the mi-

tochondrial permeability transition pore, Cell Physi-

ol. Biochem., 53, 465-479, https://doi.org/10.33594/

000000151.

34. Hurst, S., Gonnot, F., Dia, M., Crola Da Silva, C.,

Gomez, L., and Sheu, S. S. (2020) Phosphorylation

of cyclophilin D at serine 191 regulates mitochon-

drial permeability transition pore opening and cell

death after ischemia-reperfusion, Cell Death Dis.,

11, 661, https://doi.org/10.1038/s41419-020-02864-5.

BELOSLUDTSEV et al.1804

BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

35. Rasola, A., Sciacovelli, M., Chiara, F., Pantic, B.,

Brusilow, W. S., and Bernardi, P. (2010) Activation

of mitochondrial ERK protects cancer cells from

death through inhibition of the permeability transi-

tion, Proc. Natl. Acad. Sci. USA, 107, 726-731, https://

doi.org/10.1073/pnas.0912742107.

36. Coluccino,G., Negro, A., Filippi,A., Bean,C., Muraca,

V.P., Gissi,C., Canetti,D., Mimmi, M.C., Zamprogno,E.,

Ciscato, F., Acquasaliente, L., De Filippis, V., Comel-

li, M., Carraro, M., Rasola, A., Gerle, C., Bernardi, P.,

Corazza,A., and Lippe,G. (2024) N-terminal cleavage

of cyclophilin D boosts its ability to bind F-ATP syn-

thase, Commun. Biol., 7, 1486, https://doi.org/10.1038/

s42003-024-07172-8.

37. Amanakis, G., Sun, J., Fergusson, M. M., McGinty, S.,

Liu, C., Molkentin, J. D., and Murphy, E. (2021) Cys-

teine 202 of cyclophilin D is a site of multiple

post-translational modifications and plays a role

in cardioprotection, Cardiovasc. Res., 117, 212-223,

https://doi.org/10.1093/cvr/cvaa053.

38. Monné, M., and Palmieri, F. (2014) Antiporters of

the mitochondrial carrier family, Curr. Top. Membr.,

73, 289-320, https://doi.org/10.1016/B978-0-12-800223-

0.00008-6.

39. Klingenberg, M. (2008) The ADP and ATP trans-

port in mitochondria and its carrier, Biochim. Bio-

phys. Acta, 1778, 1978-2021, https://doi.org/10.1016/

j.bbamem.2008.04.011.

40. Lim, C. H., Hamazaki, T., Braun, E. L., Wade, J., and

Terada, N. (2011) Evolutionary genomics implies a

specific function of Ant4 in mammalian and anole

lizard male germ cells, PLoS One, 6, e23122, https://

doi.org/10.1371/journal.pone.0023122.

41. Clémençon, B., Babot, M., and Trézéguet, V. (2013)

The mitochondrial ADP/ATP carrier (SLC25 family):

pathological implications of its dysfunction, Mol.

Aspects Med., 34, 485-493, https://doi.org/10.1016/

j.mam.2012.05.006.

42. Brustovetsky, N. (2020) The role of adenine nucle-

otide translocase in the mitochondrial permeabili-

ty transition, Cells, 9, 2686, https://doi.org/10.3390/

cells9122686.

43. Brustovetsky, N., Tropschug, M., Heimpel, S., Heid-

kämper,D., and Klingenberg,M. (2002) Alarge Ca

-de-

pendent channel formed by recombinant ADP/ATP

carrier from Neurospora crassa resembles the mito-

chondrial permeability transition pore, Biochemistry,

41, 11804-11811, https://doi.org/10.1021/bi0200110.

44. McStay, G. P., Clarke, S.J., and Halestrap, A.P. (2002)

Role of critical thiol groups on the matrix surface

of the adenine nucleotide translocase in the mech-

anism of the mitochondrial permeability transition

pore, Biochem.J., 367, 541-548, https://doi.org/10.1042/

BJ20011672.

45. Karch, J., Bround, M. J., Khalil, H., Sargent, M. A.,

Latchman,N., Terada,N., Peixoto, P.M., and Molken-

tin, J. D. (2019) Inhibition of mitochondrial permea-

bility transition by deletion of the ANT family and

CypD, Sci Adv., 5, eaaw4597, https://doi.org/10.1126/

sciadv.aaw4597.

46. Dubinin, M.V., Talanov, E.Y., Tenkov, K.S., Starinets,

V. S., Mikheeva, I. B., Sharapov, M. G., and Beloslud-

tsev, K. N. (2020) Duchenne muscular dystrophy is

associated with the inhibition of calcium uniport

in mitochondria and an increased sensitivity of the

organelles to the calcium-induced permeability tran-

sition, Biochim. Biophys. Acta Mol. Basis Dis., 1866,

165674, https://doi.org/10.1016/j.bbadis.2020.165674.

47. Belosludtsev, K. N., Talanov, E. Y., Starinets, V. S.,

Agafonov, A. V., Dubinin, M. V., and Belosludtseva,

N. V. (2019) Transport of Ca

and Ca

-dependent

permeability transition in rat liver mitochondria un-

der the streptozotocin-induced type I diabetes, Cells,

8, 1014, https://doi.org/10.3390/cells8091014.

48. Belosludtseva, N. V., Ilzorkina, A. I., Serov, D. A.,

Dubinin, M. V., Talanov, E. Y., Karagyaur, M. N.,

Primak, A. L., Liu, J., and Belosludtsev, K. N. (2024)

ANT-mediated inhibition of the permeability tran-

sition pore alleviates palmitate-induced mitochon-

drial dysfunction and lipotoxicity, Biomolecules, 14,

1159, https://doi.org/10.3390/biom14091159.

49. Alves-Figueiredo, H., Silva-Platas, C., Lozano, O.,

Vázquez-Garza, E., Guerrero-Beltrán, C. E., Zarain-

Herzberg,A., and García-Rivas,G. (2021) Asystematic

review of post-translational modifications in the mi-

tochondrial permeability transition pore complex as-

sociated with cardiac diseases, Biochim. Biophys. Acta

Mol. Basis Dis., 1867, 165992, https://doi.org/10.1016/

j.bbadis.2020.165992.

50. Macdonald, J.E., and Ashby, P.D. (2025) Themolecu-

lar mechanism of ATP synthase constrains the evolu-

tionary landscape of chemiosmosis, Biophys. J., 124,

2103-2119, https://doi.org/10.1016/j.bpj.2025.05.017.

51. Pinke,G., Zhou,L., and Sazanov, L.A. (2020) Cryo-EM

structure of the entire mammalian F-type ATP syn-

thase, Nat. Struct. Mol. Biol., 27, 1077-1085, https://

doi.org/10.1038/s41594-020-0503-8.

52. Kinnally, K. W., Campo, M. L., and Tedeschi, H.

(1989) Mitochondrial channel activity studied by

patch-clamping mitoplasts, J.Bioenerg. Biomembr., 21,

497-506, https://doi.org/10.1007/BF00762521.

53. Urbani, A., Giorgio, V., Carrer, A., Franchin, C.,

Arrigoni, G., Jiko, C., Abe, K., Maeda, S., Shinzawa-

Itoh,K., Bogers, J.F. M., McMillan, D.G. G., Gerle,C.,

Szabò, I., and Bernardi, P. (2019) Purified F-ATP

synthase forms a Ca

-dependent high-conductance

channel matching the mitochondrial permeabili-

ty transition pore, Nat. Commun., 10, 4341, https://

doi.org/10.1038/s41467-019-12331-1.

54. Carrer, A., Tommasin, L., Šileikytė, J., Ciscato, F.,

Filadi, R., Urbani, A., Forte, M., Rasola, A., Szabò, I.,

Carraro, M., and Bernardi, P. (2021) Defining the

MPT PORE: STRUCTURE AND FUNCTIONS 1805

BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

molecular mechanisms of the mitochondrial per-

meability transition through genetic manipulation

of F-ATP synthase, Nat. Commun., 12, 4835, https://

doi.org/10.1038/s41467-021-25161-x.

55. He,J., Carroll,J., Ding,S., Fearnley, I.M., and Walker,

J. E. (2017) Permeability transition in human mito-

chondria persists in the absence of peripheral stalk

subunits of ATP synthase, Proc. Natl. Acad. Sci.

USA, 114, 9086-9091, https://doi.org/10.1073/pnas.

1711201114.

56. Carraro, M., Giorgio, V., Šileikytė, J., Sartori, G.,

Forte, M., Lippe, G., Zoratti, M., Szabò, I., and Ber-

nardi, P. (2014) Channel formation by yeast F-ATP

synthase and the role of dimerization in the mi-

tochondrial permeability transition, J.Biol. Chem.,

289, 15980-15985, https://doi.org/10.1074/jbc.C114.

559633.

57. Campanella, M., Casswell, E., Chong, S., Farah, Z.,

Wieckowski, M. R., Abramov, A. Y., Tinker, A., and

Duchen, M. R. (2008) Regulation of mitochondri-

al structure and function by the F

Fo-ATPase in-

hibitor protein, IF1, Cell Metab., 8, 13-25, https://

doi.org/10.1016/j.cmet.2008.06.001.

58. Carroll,J., He,J., Ding,S., Fearnley, I.M., and Walker,

J.E. (2019) Persistence of the permeability transition

pore in human mitochondria devoid of an assembled

ATP synthase, Proc. Natl. Acad. Sci. USA, 116, 12816-

12821, https://doi.org/10.1073/pnas.1904005116.

59. Mnatsakanyan, N., Llaguno, M. C., Yang, Y., Yan, Y.,

Weber, J., Sigworth, F. J., and Jonas, E. A. (2019)

Amitochondrial megachannel resides in monomeric

 ATP synthase, Nat. Commun., 10, 5823, https://

doi.org/10.1038/s41467-019-13766-2.

60. Alavian, K.N., Beutner,G., Lazrove,E., Sacchetti,S., Park,

H.A., Licznerski,P., Li, H., Nabili,P., Hockensmith,K.,

Graham, M., Porter, G. A., Jr., and Jonas, E. A. (2014)

An uncoupling channel within the c-subunit ring

of the F

ATP synthase is the mitochondrial

permeability transition pore, Proc. Natl. Acad. Sci.

USA, 111, 10580-10585, https://doi.org/10.1073/pnas.

1401591111.

61. Bonora, M., Bononi, A., De Marchi, E., Giorgi, C.,

Lebiedzinska, M., Marchi, S., Patergnani, S., Rimes-

si, A., Suski, J. M., Wojtala, A., Wieckowski, M. R.,

Kroemer, G., Galluzzi, L., and Pinton, P. (2013) Role

of the c subunit of the FO ATP synthase in mitochon-

drial permeability transition, Cell Cycle, 12, 674-683,

https://doi.org/10.4161/cc.23599.

62. Zhou, W., Marinelli, F., Nief, C., and Faraldo- Gómez,

J. D. (2017) Atomistic simulations indicate the c-sub-

unit ring of the F

ATP synthase is not the mi-

tochondrial permeability transition pore, Elife, 6,

e23781, https://doi.org/10.7554/eLife.23781.

63. Gerle, C. (2020) Mitochondrial F-ATP synthase as

the permeability transition pore, Pharmacol Res.,

160, 105081, https://doi.org/10.1016/j.phrs.2020.105081.

64. Morciano, G., Pedriali, G., Bonora, M., Pavasini, R.,

Mikus, E., Calvi, S., Bovolenta, M., Lebiedzinska-

Arciszewska,M., Pinotti,M., Albertini,A., Wieckowski,

M. R., Giorgi, C., Ferrari, R., Galluzzi, L., Campo, G.,

and Pinton, P. (2021) A naturally occurring muta-

tion in ATP synthase subunit c is associated with in-

creased damage following hypoxia/reoxygenation in

STEMI patients, Cell Rep., 35, 108983, https://doi.org/

10.1016/j.celrep.2021.108983.

65. He,J., Ford, H.C., Carroll,J., Ding,S., Fearnley, I.M., and

Walker, J. E. (2017) Persistence of the mitochondrial

permeability transition in the absence of subunit c of

human ATP synthase, Proc. Natl. Acad. Sci. USA, 114,

3409-3414, https://doi.org/10.1073/pnas.1702357114.

66. Neginskaya, M. A., Morris, S. E., and Pavlov, E. V.

(2022) Both ANT and ATPase are essential for mito-

chondrial permeability transition but not depolar-

ization, iScience, 25, 105447, https://doi.org/10.1016/

j.isci.2022.105447.

67. Neginskaya, M. A., Morris, S. E., and Pavlov, E. V.

(2023) Refractive index imaging reveals that elimina-

tion of the ATP synthase Csubunit does not prevent

the adenine nucleotide translocase-dependent mi-

tochondrial permeability transition, Cells, 12, 1950,

https://doi.org/10.3390/cells12151950.

68. Tommasin, L., Carrer, A., Nata, F. B., Frigo, E.,

Fogolari, F., Lippe, G., Carraro, M., and Bernardi, P.

(2025) Adenine nucleotide translocator and ATP syn-

thase cooperate in mediating the mitochondrial per-

meability transition, J.Physiol., https://doi.org/10.1113/

JP287147.

69. Richardson, A. P., and Halestrap, A. P. (2016) Quan-

tification of active mitochondrial permeability

transition pores using GNX-4975 inhibitor titra-

tions provides insights into molecular identity, Bio-

chem. J., 473, 1129-1140, https://doi.org/10.1042/

BCJ20160070.

70. Neginskaya, M.A., Strubbe, J.O., Amodeo, G.F., West,

B. A., Yakar, S., Bazil, J. N., and Pavlov, E. V. (2020)

Thevery low number of calcium-induced permeabili-

ty transition pores in the single mitochondrion, J.Gen.

Physiol., 152, e202012631, https://doi.org/10.1085/

jgp.202012631.

71. Belosludtseva, N.V., Dubinin, M.V., and Belosludtsev,

K.N. (2024) Pore-forming VDAC proteins of the outer

mitochondrial membrane: regulation and pathophys-

iological role, Biochemistry (Moscow), 89, 1061-1078,

https://doi.org/10.1134/S0006297924060075.

72. De Macedo, D.V., da Costa,C., and Pereira-Da-Silva,L.

(1997) The permeability transition pore opening in

intact mitochondria and submitochondrial parti-

cles, Comp. Biochem. Physiol. B Biochem. Mol. Biol.,

118, 209-216, https://doi.org/10.1016/s0305-0491(97)

00007-2.

73. Belosludtsev, K. N., Belosludtseva, N. V., Agafonov,

A.V., Astashev, M.E., Kazakov, A.S., Saris, N.E., and

BELOSLUDTSEV et al.1806

BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

Mironova, G. D. (2014) Ca

-dependent permeabili-

zation of mitochondria and liposomes by palmitic

and oleic acids: a comparative study, Biochim. Bio-

phys. Acta, 1838, 2600-2606, https://doi.org/10.1016/

j.bbamem.2014.06.017.

74. Baines, C. P., Kaiser, R. A., Sheiko, T., Craigen, W. J.,

and Molkentin, J. D. (2007) Voltage-dependent anion

channels are dispensable for mitochondrial-depen-

dent cell death, Nat. Cell Biol., 9, 550-555, https://

doi.org/10.1038/ncb1575.

75. Jaremko, L., Jaremko, M., Giller, K., Becker, S., and

Zweckstetter,M. (2014) Structure of the mitochondri-

al translocator protein in complex with a diagnostic

ligand, Science, 343, 1363-1366, https://doi.org/10.1126/

science.1248725.

76. Morin, D., Musman, J., Pons, S., Berdeaux, A., and

Ghaleh, B. (2016) Mitochondrial translocator protein

(TSPO): from physiology to cardioprotection, Bio-

chem. Pharmacol., 105, 1-13, https://doi.org/10.1016/

j.bcp.2015.12.003.

77. Shoshan-Barmatz, V., Pittala, S., and Mizrachi, D.

(2019) VDAC1 and the TSPO: expression, interac-

tions, and associated functions in health and disease

states, Int.J. Mol. Sci., 20, 3348, https://doi.org/10.3390/

ijms20133348.

78. Azarashvili, T., Grachev, D., Krestinina, O.,

Evtodienko, Y., Yurkov, I., Papadopoulos, V., and

Reiser, G. (2007) The peripheral-type benzodiazepine

receptor is involved in control of Ca

-induced per-

meability transition pore opening in rat brain mi-

tochondria, Cell Calcium, 42, 27-39, https://doi.org/

10.1016/j.ceca.2006.11.004.

79. Šileikytė, J., Blachly-Dyson, E., Sewell, R., Carpi, A.,

Menabò,R., Di Lisa, F., Ricchelli, F., Bernardi, P., and

Forte,M. (2014) Regulation of the mitochondrial per-

meability transition pore by the outer membrane

does not involve the peripheral benzodiazepine re-

ceptor (Translocator Protein of 18kDa (TSPO)), J.Biol.

Chem., 289, 13769-13781, https://doi.org/10.1074/

jbc.M114.549634.

80. Whelan, R.S., Konstantinidis,K., Wei, A.C., Chen, Y.,

Reyna, D.E., Jha,S., Yang,Y., Calvert, J.W., Lindsten,T.,

Thompson, C. B., Crow, M. T., Gavathiotis, E., Dorn,

G. W., 2nd, O’Rourke,B., and Kitsis, R. N. (2012) Bax

regulates primary necrosis through mitochondrial

dynamics, Proc. Natl. Acad. Sci. USA, 109, 6566-6571,

https://doi.org/10.1073/pnas.1201608109.

81. Gutiérrez-Aguilar, M., Douglas, D. L., Gibson, A. K.,

Domeier, T. L., Molkentin, J. D., and Baines, C. P.

(2014) Genetic manipulation of the cardiac mito-

chondrial phosphate carrier does not affect perme-

ability transition, J. Mol. Cell Cardiol., 72, 316-325,

https://doi.org/10.1016/j.yjmcc.2014.04.008.

82. Nikiforova, A.B., Baburina, Y.L., Borisova, M.P., Surin,

A. K., Kharechkina, E. S., Krestinina, O. V., Suvorina,

M.Y., Kruglova, S.A., and Kruglov, A.G. (2023) Mito-

chondrial F-ATP synthase co-migrating proteins and

-dependent formation of large channels, Cells, 12,

414, https://doi.org/10.3390/cells12192414.

83. Shanmughapriya,S., Rajan,S., Hoffman, N.E., Higgins,

A.M., Tomar,D., Nemani,N., Hines, K.J., Smith, D.J.,

Eguchi,A., Vallem,S., Shaikh,F., Cheung,M., Leonard,

N.J., Stolakis, R.S., Wolfers, M.P., Ibetti,J., Chuprun,

J.K., Jog, N.R., Houser, S.R., Koch, W.J., Elrod, J.W.,

and Madesh, M. (2015) SPG7 is an essential and

conserved component of the mitochondrial perme-

ability transition pore, Mol. Cell, 60, 47-62, https://

doi.org/10.1016/j.molcel.2015.08.009.

84. Hurst, S., Baggett, A., Csordas, G., and Sheu, S. S.

(2019) SPG7 targets the m-AAA protease complex to

process MCU for uniporter assembly, Ca

influx, and

regulation of mitochondrial permeability transition

pore opening, J.Biol. Chem., 294, 10807-10818, https://

doi.org/10.1074/jbc.RA118.006443.

85. Sambri, I., Massa, F., Gullo, F., Meneghini, S.,

Cassina, L., Carraro, M., Dina, G., Quattrini, A.,

Patanella, L., Carissimo, A., Iuliano, A., Santorelli, F.,

Codazzi, F., Grohovaz, F., Bernardi, P., Becchetti, A.,

and Casari, G. (2020) Impaired flickering of the per-

meability transition pore causes SPG7 spastic para-

plegia, EBioMedicine, 61, 103050, https://doi.org/

10.1016/j.ebiom.2020.103050.

86. Klutho, P. J., Dashek, R. J., Song, L., and Baines, C. P.

(2020) Genetic manipulation of SPG7 or NipSnap2

does not affect mitochondrial permeability transi-

tion, Cell Death Discov., 6, 5, https://doi.org/10.1038/

s41420-020-0239-6.

87. Dolder,M., Wendt,S., and Wallimann,T. (2001) Mito-

chondrial creatine kinase in contact sites: interaction

with porin and adenine nucleotide translocase, role

in permeability transition and sensitivity to oxida-

tive damage, Biol. Signals Recept., 10, 93-111, https://

doi.org/10.1159/000046878.

88. Smeele, K. M., Southworth, R., Wu, R., Xie, C.,

Nederlof,R., Warley,A., Nelson, J.K., van Horssen,P.,

van den Wijngaard, J. P., Heikkinen, S., Laakso, M.,

Koeman, A., Siebes, M., Eerbeek, O., Akar, F. G.,

Ardehali, H., Hollmann, M. W., and Zuurbier, C. J.

(2011) Disruption of hexokinase II-mitochondrial

binding blocks ischemic preconditioning and caus-

es rapid cardiac necrosis, Circ. Res., 108, 1165-1169,

https://doi.org/10.1161/CIRCRESAHA.111.244962.

89. Juhaszova, M., Wang, S., Zorov, D. B., Nuss, H. B.,

Gleichmann,M., Mattson, M.P., and Sollott, S.J. (2008)

Theidentity and regulation of the mitochondrial per-

meability transition pore: where the known meets

the unknown, Ann. N. Y. Acad. Sci., 1123, 197-212,

https://doi.org/10.1196/annals.1420.023.

90. Guo, D., Meng, Y., Jiang, X., and Lu, Z. (2023) Hex-

okinases in cancer and other pathologies, Cell In-

sight., 2, 100077, https://doi.org/10.1016/j.cellin.2023.

100077.

MPT PORE: STRUCTURE AND FUNCTIONS 1807

BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

91. Zoratti, M., Szabò, I., and De Marchi, U. (2005) Mito-

chondrial permeability transitions: how many doors

to the house? Biochim. Biophys. Acta, 1706, 40-52,

https://doi.org/10.1016/j.bbabio.2004.10.006.

92. Sultan,A., and Sokolove,P. (2001) Palmitic acid opens

a novel cyclosporin A-insensitive pore in the inner

mitochondrial membrane, Arch. Biochem. Biophys.,

386, 31-51, https://doi.org/10.1006/abbi.2000.2194.

93. Agafonov, A., Gritsenko, E., Belosludtsev, K.,

Kovalev, A., Gateau-Roesch, O., Saris, N.-E. L., and

Mironova, G. D. (2003) A permeability transition in

liposomes induced by the formation of Ca

/palmitic

acid complexes, Biochim. Biophys. Acta, 1609, 153-

160, https://doi.org/10.1016/S0005-2736(02)00666-1.

94. Belosludtseva, N. V., Pavlik, L. L., Belosludtsev, K.N.,

Saris, N.L., Shigaeva, M.I., and Mironova, G.D. (2022)

Theshort-term opening of cyclosporin A-independent

palmitate/Sr

-induced pore can underlie ion efflux

in the oscillatory mode of functioning of rat liver

mitochondria, Membranes (Basel), 12, 667, https://

doi.org/10.3390/membranes12070667.

95. Šileikytė, J., and Forte, M. (2016) Shutting down the

pore: the search for small molecule inhibitors of the

mitochondrial permeability transition, Biochim. Bio-

phys. Acta, 1857, 1197-1202, https://doi.org/10.1016/

j.bbabio.2016.02.016.

96. Efimov, S.V., Dubinin, M.V., Kobchikova, P.P., Zgadzay,

Y.O., Khodov, I.A., Belosludtsev, K.N., and Klochkov,

V. V. (2020) Comparison of cyclosporin variants B-E

based on their structural properties and activity in

mitochondrial membranes, Biochem. Biophys. Res.

Commun., 526, 1054-1060, https://doi.org/10.1016/

j.bbrc.2020.03.184.

97. Rosenwirth, B., Billich, A., Datema, R., Donatsch, P.,

Hammerschmid, F., Harrison, R., Hiestand, P.,

Jaksche,H., Mayer,P., and Peichl,P. (1994) Inhibition

of human immunodeficiency virus type1 replication

by SDZ NIM 811, a nonimmunosuppressive cyclospo-

rine analog, Antimicrob. Agents Chemother., 38, 1763-

1772, https://doi.org/10.1128/AAC.38.8.1763.

98. Reutenauer, J., Dorchies, O. M., Patthey-Vuadens, O.,

Vuagniaux, G., and Ruegg, U. T. (2008) Investigation

of Debio 025, a cyclophilin inhibitor, in the dystro-

phic mdx mouse, a model for Duchenne muscular

dystrophy, Br. J. Pharmacol., 155, 574-584, https://

doi.org/10.1038/bjp.2008.285.

99. Dubinin, M.V., Starinets, V.S., Talanov, E.Y., Mikheeva,

I. B., Belosludtseva, N. V., and Belosludtsev, K. N.

(2021) Alisporivir improves mitochondrial function

in skeletal muscle of mdx mice but suppresses mito-

chondrial dynamics and biogenesis, Int.J. Mol. Sci.,

22, 9780, https://doi.org/10.3390/ijms22189780.

100. Tiepolo, T., Angelin, A., Palma, E., Sabatelli, P.,

Merlini, L., Nicolosi, L., Finetti, F., Braghetta, P.,

Vuagniaux,G., Dumont, J.M., Baldari, C.T., Bonaldo,P.,

and Bernardi, P. (2009) The cyclophilin inhibitor

Debio 025 normalizes mitochondrial function, mus-

cle apoptosis and ultrastructural defects in Col6a1

–/–

myopathic mice, Br. J. Pharmacol., 157, 1045-1052,

https://doi.org/10.1111/j.1476-5381.2009.00316.x.

101. Montagne, A., Nikolakopoulou, A. M., Huuskonen,

M.T., Sagare, A.P., Lawson, E.J., Lazic,D., Rege, S.V.,

Grond,A., Zuniga,E., Barnes, S.R., Prince,J., Sagare,M.,

Hsu, C.J., LaDu, M.J., Jacobs, R.E., and Zlokovic, B.V.

(2021) APOE4 accelerates advanced-stage vascular

and neurodegenerative disorder in old Alzheimer’s

mice via cyclophilin A independently of amyloid-β,

Nat. Aging, 1, 506-520, https://doi.org/10.1038/s43587-

021-00073-z.

102. Dubinin, M.V., Sharapov, V.A., Ilzorkina, A.I., Efimov,

S.V., Klochkov, V. V., Gudkov, S. V., and Belosludtsev,

K.N. (2022) Comparison of structural properties of cy-

closporinA and its analogue alisporivir and their ef-

fects on mitochondrial bioenergetics and membrane

behavior, Biochim. Biophys. Acta Biomembr., 1864,

183972, https://doi.org/10.1016/j.bbamem.2022.183972.

103. Schaller, S., Paradis, S., Ngoh, G. A., Assaly, R.,

Buisson, B., Drouot, C., Ostuni, M. A., Lacapere, J. J.,

Bassissi, F., Bordet, T., Berdeaux, A., Jones, S. P.,

Morin, D., and Pruss, R. M. (2010) TRO40303, a new

cardioprotective compound, inhibits mitochondrial

permeability transition, J.Pharmacol. Exp. Ther., 333,

696-706, https://doi.org/10.1124/jpet.110.167486.

104. Clarke, S.J., McStay, G.P., and Halestrap, A.P. (2002)

Sanglifehrin A acts as a potent inhibitor of the mi-

tochondrial permeability transition and reperfusion

injury of the heart by binding to cyclophilin-D at a

different site from cyclosporinA, J.Biol. Chem., 277,

34793-34799, https://doi.org/10.1074/jbc.M202191200.

105. Lim, S.Y., Davidson, S.M., Hausenloy, D.J., and Yellon,

D. M. (2007) Preconditioning and postconditioning:

the essential role of the mitochondrial permeability

transition pore, Cardiovasc. Res., 75, 530-535, https://

doi.org/10.1016/j.cardiores.2007.04.022.

106. Albanese, V., Pedriali, G., Fabbri, M., Ciancetta, A.,

Ravagli, S., Roccatello, C., Guerrini, R., Morciano, G.,

Preti, D., Pinton, P., and Pacifico, S. (2025) Design

and synthesis of 1,4,8-triazaspiro[4.5]decan-2-one de-

rivatives as novel mitochondrial permeability tran-

sition pore inhibitors, J.Enzyme Inhib. Med. Chem.,

40, 2505907, https://doi.org/10.1080/14756366.2025.

2505907.

107. Fancelli, D., Abate, A., Amici, R., Bernardi, P.,

Ballarini, M., Cappa, A., Carenzi, G., Colombo, A.,

Contursi, C., Di Lisa, F., Dondio, G., Gagliardi, S.,

Milanesi, E., Minucci, S., Pain, G., Pelicci, P. G.,

Saccani,A., Storto,M., Thaler,F., Varasi,M., Villa,M.,

and Plyte, S. (2014) Cinnamic anilides as new mito-

chondrial permeability transition pore inhibitors en-

dowed with ischemia-reperfusion injury protective

effect in vivo, J. Med. Chem., 57, 5333-5347, https://

doi.org/10.1021/jm500547c.

BELOSLUDTSEV et al.1808

BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

108. Šileikytė, J., Devereaux, J., de Jong, J., Schiavone, M.,

Jones, K., Nilsen, A., Bernardi, P., Forte, M., and

Cohen, M. S. (2019) Second-generation inhibitors

of the mitochondrial permeability transition pore

with improved plasma stability, ChemMedChem, 14,

1771-1782, https://doi.org/10.1002/cmdc.201900376.

109. Roy,S., Šileikytė,J., Schiavone,M., Neuenswander,B.,

Argenton, F., Aubé, J., Hedrick, M. P., Chung, T. D.,

Forte, M. A., Bernardi, P., and Schoenen, F. J. (2015)

Discovery, synthesis, and optimization of diaryli-

soxazole-3-carboxamides as potent inhibitors of

the mitochondrial permeability transition pore,

ChemMedChem, 10, 1655-1671, https://doi.org/10.1002/

cmdc.201500284.

110. Stocco, A., Smolina, N., Sabatelli, P., Šileikytė, J.,

Artusi, E., Mouly, V., Cohen, M., Forte, M.,

Schiavone, M., and Bernardi, P. (2021) Treatment

with a triazole inhibitor of the mitochondrial per-

meability transition pore fully corrects the patholo-

gy of sapje zebrafish lacking dystrophin, Pharmacol

Res., 165, 105421, https://doi.org/10.1016/j.phrs.2021.

105421.

111. Bernardi, P., Krauskopf, A., Basso, E., Petronilli, V.,

Blachly-Dyson, E., Di Lisa, F., and Forte, M. A. (2006)

Themitochondrial permeability transition from in vi-

tro artifact to disease target, FEBSJ., 273, 2077-2099,

https://doi.org/10.1111/j.1742-4658.2006.05213.x.

112. Panel,M., Ghaleh,B., and Morin,D. (2018) Mitochon-

dria and aging: Arole for the mitochondrial transition

pore? Aging Cell, 17, e12793, https://doi.org/10.1111/

acel.12793.

113. Angeli, S., Foulger, A., Chamoli, M., Peiris, T. H.,

Gerencser, A., Shahmirzadi, A. A., Andersen, J., and

Lithgow, G. (2021) The mitochondrial permeability

transition pore activates the mitochondrial unfold-

ed protein response and promotes aging, Elife, 10,

e63453, https://doi.org/10.7554/eLife.63453.

114. Du, H., Guo, L., Fang, F., Chen, D., Sosunov, A. A.,

McKhann, G. M., Yan, Y., Wang, C., Zhang, H.,

Molkentin, J. D., Gunn-Moore, F. J., Vonsattel, J. P.,

Arancio, O., Chen, J. X., and Yan, S. D. (2008) Cyclo-

philin D deficiency attenuates mitochondrial and

neuronal perturbation and ameliorates learning and

memory in Alzheimer’s disease, Nat. Med., 14, 1097-

1105, https://doi.org/10.1038/nm.1868.

115. Zhu, Y., Duan, C., Lü, L., Gao, H., Zhao, C., Yu, S.,

Uéda, K., Chan, P., and Yang, H. (2011) α-Synuclein

overexpression impairs mitochondrial function by

associating with adenylate translocator, Int. J. Bio-

chem. Cell Biol., 43, 732-741, https://doi.org/10.1016/

j.biocel.2011.01.014.

116. Belosludtseva, N.V., Matveeva, L.A., and Belosludtsev,

K. N. (2023) Mitochondrial dyshomeostasis as an

early hallmark and a therapeutic target in amyo-

trophic lateral sclerosis, Int.J. Mol. Sci., 24, 16833,

https://doi.org/10.3390/ijms242316833.

117. Singh,S., Ganguly,U., Pal,S., Chandan,G., Thakur,R.,

Saini, R. V., Chakrabarti, S. S., Agrawal, B. K., and

Chakrabarti, S. (2022) Protective effects of cyclospo-

rineA on neurodegeneration and motor impairment

in rotenone-induced experimental models of Parkin-

son’s disease, Eur.J. Pharmacol., 929, 175129, https://

doi.org/10.1016/j.ejphar.2022.175129.

118. Bordet, T., Berna, P., Abitbol, J. L., and Pruss, R. M.

(2010) Olesoxime (TRO19622): a novel mitochon-

drial-targeted neuroprotective compound, Pharma-

ceuticals (Basel), 3, 345-368, https://doi.org/10.3390/

ph3020345.

119. Argaud, L., Gateau-Roesch, O., Muntean, D.,

Chalabreysse, L., Loufouat, J., Robert, D., and

Ovize, M. (2005) Specific inhibition of the mito-

chondrial permeability transition prevents lethal

reperfusion injury, J. Mol. Cell Cardiol., 38, 367-374,

https://doi.org/10.1016/j.yjmcc.2004.12.001.

120. Nakagawa,T., Shimizu,S., Watanabe,T., Yamaguchi,O.,

Otsu, K., Yamagata, H., Inohara, H., Kubo, T., and

Tsujimoto, Y. (2005) Cyclophilin D-dependent mito-

chondrial permeability transition regulates some ne-

crotic but not apoptotic cell death, Nature, 434, 652-

658, https://doi.org/10.1038/nature03317.

121. Cung, T. T., Morel, O., Cayla, G., Rioufol, G., Garcia-

Dorado, D., Angoulvant, D., Bonnefoy-Cudraz, E.,

Guérin,P., Elbaz,M., Delarche,N., Coste,P., Vanzetto,G.,

Metge,M., Aupetit, J.F., Jouve,B., Motreff,P., Tron,C.,

Labeque, J. N., Steg, P. G., et al. (2015) Cyclosporine

before PCI in patients with acute myocardial infarc-

tion, N.Engl.J. Med., 373, 1021-1031, https://doi.org/

10.1056/NEJMoa1505489.

122. Wrogemann,K., and Pena, S.D. (1976) Mitochondrial

calcium overload: a general mechanism for cell-

necrosis in muscle diseases, Lancet, 1, 672-674, https://

doi.org/10.1016/s0140-6736(76)92781-1.

123. Zulian,A., Schiavone,M., Giorgio,V., and Bernardi,P.

(2016) Forty years later: mitochondria as therapeu-

tic targets in muscle diseases, Pharmacol. Res., 113,

563-573, https://doi.org/10.1016/j.phrs.2016.09.043.

124. Millay, D. P., Sargent, M. A., Osinska, H., Baines,

C. P., Barton, E. R., Vuagniaux, G., Sweeney, H. L.,

Robbins, J., and Molkentin, J. D. (2008) Genetic and

pharmacologic inhibition of mitochondrial-dependent

necrosis attenuates muscular dystrophy, Nat. Med.,

14, 442-447, https://doi.org/10.1038/nm1736.

125. Dubinin, M. V., and Belosludtsev, K. N. (2023) Ion

channels of the sarcolemma and intracellular or-

ganelles in duchenne muscular dystrophy: a role in

the dysregulation of ion homeostasis and a possible

target for therapy, Int.J. Mol. Sci., 24, 2229, https://

doi.org/10.3390/ijms24032229.

126. Wang, P., Zhang, N., Wu, B., Wu, S., Zhang, Y., and

Sun, Y. (2020) The role of mitochondria in vascular

calcification, J.Transl. Int. Med., 8, 80-90, https://

doi.org/10.2478/jtim-2020-0013.

MPT PORE: STRUCTURE AND FUNCTIONS 1809

BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

127. Dubinin, M.V., Talanov, E.Y., Tenkov, K.S., Starinets,

V. S., Mikheeva, I. B., and Belosludtsev, K. N. (2020)

Transport of Ca

and Ca

-dependent permeability

transition in heart mitochondria in the early stages

of Duchenne muscular dystrophy, Biochim. Biophys.

Acta Bioenerg., 1861, 148250, https://doi.org/10.1016/

j.bbabio.2020.148250.

128. Bround, M. J., Havens, J. R., York, A. J., Sargent,

M. A., Karch, J., and Molkentin, J. D. (2023) ANT-

dependent MPTP underlies necrotic myofiber death

in muscular dystrophy, Sci. Adv., 9, eadi2767, https://

doi.org/10.1126/sciadv.adi2767.

129. Belosludtseva, N. V., Ilzorkina, A. I., Dubinin, M. V.,

Mikheeva, I. B., and Belosludtsev, K. N. (2025) Com-

parative study of structural and functional rearrange-

ments in skeletal muscle mitochondria of SOD1-G93A

transgenic mice at pre-, early-, and late-symptomatic

stages of ALS progression, Front. Biosci. (Landmark

Ed), 30, 28260, https://doi.org/10.31083/FBL28260.

130. Hepple, R. T. (2016) Impact of aging on mitochon-

drial function in cardiac and skeletal muscle, Free

Radic. Biol. Med., 98, 177-186, https://doi.org/10.1016/

j.freeradbiomed.2016.03.017.

131. Belosludtsev, K.N., Belosludtseva, N.V., and Dubinin,

M. V. (2020) Diabetes mellitus, mitochondrial dys-

function and Ca

-dependent permeability transition

pore, Int.J. Mol. Sci., 21, 6559, https://doi.org/10.3390/

ijms21186559.

132. Lablanche, S., Cottet-Rousselle, C., Lamarche, F.,

Benhamou, P. Y., Halimi, S., Leverve, X., and Fon-

taine,E. (2011) Protection of pancreatic INS-1 β-cells

from glucose- and fructose-induced cell death by in-

hibiting mitochondrial permeability transition with

cyclosporinA or metformin, Cell Death Dis., 2, e134,

https://doi.org/10.1038/cddis.2011.15.

133. Belosludtseva, N. V., Starinets, V. S., Mikheeva, I. B.,

Serov, D. A., Astashev, M. E., Belosludtsev, M. N.,

Dubinin, M. V., and Belosludtsev, K. N. (2021) Effect

of the MPT pore inhibitor alisporivir on the devel-

opment of mitochondrial dysfunction in the heart

tissue of diabetic mice, Biology (Basel), 10, 839,

https://doi.org/10.3390/biology10090839.

134. Couturier,K., Hininger,I., Poulet, L., Anderson, R. A.,

Roussel, A. M., Canini, F., and Batandier, C. (2016)

Cinnamon intake alleviates the combined effects of

dietary-induced insulin resistance and acute stress

on brain mitochondria, J.Nutr. Biochem., 28, 183-190,

https://doi.org/10.1016/j.jnutbio.2015.10.016.

135. Oliveira, P. J., Seiça, R., Coxito, P. M., Rolo, A. P.,

Palmeira, C.M., Santos, M.S., and Moreno, A.J. (2003)

Enhanced permeability transition explains the re-

duced calcium uptake in cardiac mitochondria from

streptozotocin-induced diabetic rats, FEBS Lett., 554,

511-514, https://doi.org/10.1016/s0014-5793(03)01233-x.

136. Monaco, C. M. F., Hughes, M. C., Ramos, S. V., Varah,

N. E., Lamberz, C., Rahman, F. A., McGlory, C.,

Tarnopolsky, M. A., Krause, M.P., Laham, R., Hawke,

T.J., and Perry, C.G. R. (2018) Altered mitochondrial

bioenergetics and ultrastructure in the skeletal mus-

cle of young adults with type 1 diabetes, Diabetolo-

gia, 61, 1411-1423, https://doi.org/10.1007/s00125-018-

4602-6.

137. Ferreira, F. M., Seiça, R., Oliveira, P. J., Coxito, P. M.,

Moreno, A.J., Palmeira, C.M., and Santos, M.S. (2003)

Diabetes induces metabolic adaptations in rat liver

mitochondria: role of coenzyme Q and cardiolip-

in contents, Biochim. Biophys. Acta, 1639, 113-120,

https://doi.org/10.1016/j.bbadis.2003.08.001.

138. Teodoro, J. S., Rolo, A.P., Duarte, F.V., Simões, A.M.,

and Palmeira, C.M. (2008) Differential alterations in

mitochondrial function induced by a choline-deficient

diet: understanding fatty liver disease progression,

Mitochondrion, 8, 367-376, https://doi.org/10.1016/

j.mito.2008.07.008.

139. Taddeo, E. P., Laker, R. C., Breen, D.S., Akhtar, Y. N.,

Kenwood, B. M., Liao, J. A., Zhang, M., Fazakerley,

D.J., Tomsig, J.L., Harris, T.E., Keller, S.R., Chow, J.D.,

Lynch, K. R., Chokki, M., Molkentin, J. D., Turner, N.,

James, D. E., Yan, Z., and Hoehn, K. L. (2013) Open-

ing of the mitochondrial permeability transition pore

links mitochondrial dysfunction to insulin resistance

in skeletal muscle, Mol. Metab., 3, 124-134, https://

doi.org/10.1016/j.molmet.2013.11.003.

140. Belosludtsev, K. N., Starinets, V. S., Talanov, E. Y.,

Mikheeva, I. B., Dubinin, M. V., and Belosludtseva,

N.V. (2021) Alisporivir treatment alleviates mitochon-

drial dysfunction in the skeletal muscles of C57BL/

6NCrl mice with high-fat diet/streptozotocin-induced

diabetes mellitus, Int.J. Mol. Sci., 22, 9524, https://

doi.org/10.3390/ijms22179524.

141. Starinets, V. S., Serov, D. A., Penkov, N. V., Beloslud-

tseva, N. V., Dubinin, M. V., and Belosludtsev, K. N.

(2022) Alisporivir normalizes mitochondrial function

of primary mouse lung endothelial cells under con-

ditions of hyperglycemia, Biochemistry (Moscow), 87,

605-616, https://doi.org/10.1134/S0006297922070033.

142. Belosludtsev, K.N., Serov, D.A., Ilzorkina, A.I., Stari-

nets, V. S., Dubinin, M. V., Talanov, E. Y., Karagyaur,

M. N., Primak, A. L., and Belosludtseva, N. V. (2023)

Pharmacological and genetic suppression of VDAC1

alleviates the development of mitochondrial dys-

function in endothelial and fibroblast cell cultures

upon hyperglycemic conditions, Antioxidants (Basel),

12, 1459, https://doi.org/10.3390/antiox12071459.

143. Zhu, X., Qin, Z., Zhou, M., Li, C., Jing, J., Ye, W., and

Gan, X. (2024) The role of mitochondrial permea-

bility transition in bone metabolism, bone healing,

and bone diseases, Biomolecules, 14, 1318, https://

doi.org/10.3390/biom14101318.

144. Sautchuk, R., Kalicharan, B. H., Escalera-Rivera, K.,

Jonason, J.H., Porter, G.A., Awad, H.A., and Eliseev,

R.A. (2022) Transcriptional regulation of cyclophilinD

BELOSLUDTSEV et al.1810

BIOCHEMISTRY (Moscow) Vol. 90 No. 12 2025

by BMP/Smad signaling and its role in osteogenic dif-

ferentiation, Elife, 11, e75023, https://doi.org/10.7554/

eLife.75023.

145. Shares, B.H., Smith, C.O., Sheu, T.J., Sautchuk,R.,Jr.,

Schilling,K., Shum, L.C., Paine,A., Huber,A., Gira,E.,

Brown, E., Awad, H., and Eliseev, R. A. (2020) Inhi-

bition of the mitochondrial permeability transition

improves bone fracture repair, Bone, 137, 115391,

https://doi.org/10.1016/j.bone.2020.115391.

146. He,Y., Zhang,L., Zhu,Z., Xiao,A., Yu,H., and Gan,X.

(2017) Blockade of cyclophilinD rescues dexametha-

sone-induced oxidative stress in gingival tissue, PLoS

One, 12, e0173270, https://doi.org/10.1371/journal.

pone.0173270.

147. He, P., Liu, F., Li, M., Ren, M., Wang, X., Deng, Y.,

Wu, X., Li, Y., Yang, S., and Song, J. (2023) Mitochon-

drial calcium ion nanogluttons alleviate periodon-

titis via controlling mPTPs, Adv. Health. Mater., 12,

e2203106, https://doi.org/10.1002/adhm.202203106.

148. Bonora, M., and Pinton, P. (2014) The mitochondrial

permeability transition pore and cancer: molecular

mechanisms involved in cell death, Front. Oncol., 4,

302, https://doi.org/10.3389/fonc.2014.00302.

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