title: HSP90 cross-links branched actin filaments induced by N-WASP and the Arp2/3 complex.
abstract: N-WASP induces filopodial actin cytoskeleton through activation of the Arp2/3 complex. Here, we show that heat shock protein 90 (HSP90) regulates the structure of actin filaments induced by N-WASP and the Arp2/3 complex. HSP90 binds to N-WASP and to F-actin and bundles actin filaments. Bundling activity of HSP90 does not affect actin filament nucleation induced by N-WASP and the Arp2/3 complex. HSP90 is co-localized with N-WASP at branching points of actin filaments produced by the Arp2/3 complex and thereby bundles branched filaments; this bundled actin structure is inhibited by blocking direct binding between HSP90 and N-WASP. Furthermore, HSP90 converts branched actin filaments on N-WASP-coated beads to filopodia-like star-shaped bundles. These findings indicate that HSP90 promotes the formation of N-WASP/Arp2/3 complex-induced unbranched filopodial actin structures.
authors.affiliation: Department of Biochemistry, Institute of Medical Science, University of Tokyo, Tokyo 108-8539, Japan; 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8539, Japan.
authors.forename: Sun Joo
authors.initials: SJ
authors.lastname: Park
authors.forename: Shiro
authors.initials: S
authors.lastname: Suetsugu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sagara
authors.forename: Tadaomi
authors.initials: T
authors.lastname: Takenawa
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000737:chemistry / Q000378:metabolism*; D000199:Actins / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D002417:Cattle; D002460:Cell Line; D003432:Cross-Linking Reagents; D018841:HSP90 Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D066298:In Vitro Techniques; D007700:Kinetics; D008854:Microscopy, Electron; D046912:Multiprotein Complexes; D011485:Protein Binding; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal / Q000737:chemistry / Q000378:metabolism*
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D003432:Cross-Linking Reagents; D018841:HSP90 Heat-Shock Proteins; D046912:Multiprotein Complexes; D011994:Recombinant Proteins; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal