title: Heat shock protein (hsp90) interacts with smooth muscle calponin and affects calponin-binding to actin.
abstract: Interaction of smooth muscle calponin with 90 kDa heat shock protein (hsp90) was analyzed by means of native gel electrophoresis and affinity chromatography. Under conditions used, calponin and hsp90 form a complex with an apparent dissociation constant in the micromolar range. The major hsp90-binding site is located in the N-terminal (residues 7-144) part of calponin. Addition of calponin to actin-tropomyosin complex results in formation of actin bundles. Hsp90 partially prevents bundle formation without affecting the molar ratio calponin/actin in single actin filaments or actin bundles. At low ionic strength, calponin induces polymerization of G-actin. Hsp90 decreases calponin-induced polymerization of G-actin. It is supposed that hsp90 may be involved in the assembly of actin filaments.
authors.affiliation: Department of Biochemistry, School of Biology, Moscow State University, Moscow, Russia.
authors.forename: Y
authors.initials: Y
authors.lastname: Ma
authors.forename: N V
authors.initials: NV
authors.lastname: Bogatcheva
authors.forename: N B
authors.initials: NB
authors.lastname: Gusev
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D008840:Microfilament Proteins; D009130:Muscle, Smooth / Q000378:metabolism; D011485:Protein Binding; D000096985:Calponins
chemical_list: D000199:Actins; D002135:Calcium-Binding Proteins; D018841:HSP90 Heat-Shock Proteins; D008840:Microfilament Proteins; D000096985:Calponins