REVIEW: Is RsfS a Hibernation Factor or a Ribosome Biogenesis Factor?

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Bulat F. Fatkhullin^1,2,a*, Azat G. Gabdulkhakov¹, and Marat M. Yusupov^2,3

¹Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia

²Institute of Genetics and Molecular and Cellular Biology, F-67400 Illkirsch-Graffenstaden, France

³Laboratory of Structural Analyze of Biomacromolecules, Federal Research Center “Kazan Scientific Center of the Russian Academy of Sciences”, 420111 Kazan, Russia

^* To whom correspondence should be addressed.

Received December 31, 2021; Revised April 20, 2022; Accepted April 20, 2022

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Solving the structures of bacterial, archaeal, and eukaryotic ribosomes by crystallography and cryo-electron microscopy has given an impetus for studying intracellular regulatory proteins affecting various stages of protein translation. Among them are ribosome hibernation factors, which have been actively investigated during the last decade. These factors are involved in the regulation of protein biosynthesis under stressful conditions. The main role of hibernation factors is the reduction of energy consumption for protein biosynthesis and preservation of existing functional ribosomes from degradation, which increases cell survival under unfavorable conditions. Despite a broad interest in this topic, only a few articles have been published on the ribosomal silencing factor S (RsfS). According to the results of these studies, RsfS can be assigned to the group of hibernation factors. However, recent structural studies of the 50S ribosomal subunit maturation demonstrated that RsfS has the features inherent to biogenesis factors for example, ability to bind to the immature ribosomal subunit (similar to the RsfS mitochondrial ortholog MALSU1, mitochondrial assembly of ribosomal large subunit 1). In this review, we summarized the information on the function and structural features RsfS, as well as compared RsfS with MALSU1 in order to answer the emerging question on whether RsfS is a hibernation factor or a ribosome biogenesis factor. We believe that this review might promote future studies of the RsfS-involving molecular mechanisms, which so far remain completely unknown.

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KEY WORDS: ribosome, ribosome biogenesis factor, hibernation factor, RsfS

DOI: 10.1134/S0006297922060025

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