Isolation of Rabbit Liver Heat Shock Protein with Molecular Weight 90 kD (Hsp90) and Its Interaction with Troponin Components and Calponin

YuShu Ma, N. V. Bogatcheva, and N. B. Gusev^*

Department of Biochemistry, School of Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-3955; E-mail: Gusev@gusev.bio.msu.su

^* To whom correspondence should be addressed.

Received January 20, 1998; Revision received June 15, 1998

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Using a modified method consisting of chromatography on phenyl-Sepharose, Q-Sepharose, and hydroxyapatite, we isolated a highly purified heat shock protein with molecular weight 90 kD (Hsp90) from rabbit liver. The isolated protein was recognized on immunoblot by commercially available monoclonal anti-Hsp90 antibodies. The chromatographic properties, interaction with actin and calmodulin, phosphorylation in the presence of Mg-ATP, and one-dimensional peptide maps of rabbit liver Hsp90 are similar to the corresponding properties of Hsp90 isolated from other sources. In the presence of soluble carbodiimide and N-hydroxysuccinimide, rabbit liver Hsp90 can be cross-linked with calmodulin, troponin C, troponin I, and calponin. The data obtained indicate that Hsp90 may participate in the assembly of regulatory proteins of the actin filament.

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KEY WORDS: heat shock protein, troponin components, calponin

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