title: Chaperone activity of alpha B-crystallin suppresses tubulin aggregation through complex formation.
abstract: alpha B-Crystallin, one of the small heat shock proteins, is constitutively expressed in lens as well as in nonlenticular tissues. It can function as a molecular chaperone for other lens crystallins and some other proteins. Its nonocular function is unknown although some reported one of them is related to cytoskeletal networks and/or components. In the present study, we demonstrate the association of alpha B-crystallin with tubulin. Immunoprecipitation experiments using L6 myoblast cell lysate with anti-alpha B-crystallin antibody resulted in the coprecipitation of alpha-tubulin, which was apparently temperature-dependent. Further, purified alpha B-crystallin prevented the turbidity development of purified tubulin molecule at 37 degrees C in vitro. Sucrose gradient centrifugation revealed that this chaperone activity was accompanied by the formation of large complex of alpha B-crystallin and tubulin dimer. These results indicate that one of the nonlenticular functions of alpha B-crystallin may be the protection of tubulin subunits of microtubules.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Arai
authors.forename: Y
authors.initials: Y
authors.lastname: Atomi
mesh_terms: D000818:Animals; D000906:Antibodies / Q000378:metabolism; D002458:Cell Fractionation; D002460:Cell Line; D003459:Crystallins / Q000276:immunology / Q000494:pharmacology*; D006360:Heat-Shock Proteins / Q000276:immunology / Q000494:pharmacology*; D015151:Immunoblotting; D008870:Microtubules / Q000378:metabolism; D018832:Molecular Chaperones / Q000494:pharmacology*; D011233:Precipitin Tests; D014404:Tubulin / Q000276:immunology / Q000378:metabolism; D050257:Tubulin Modulators
chemical_list: D000906:Antibodies; D003459:Crystallins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D014404:Tubulin; D050257:Tubulin Modulators