title: Interaction of HSP90 to N-WASP leads to activation and protection from proteasome-dependent degradation.
abstract: Neural Wiskott-Aldrich syndrome protein (N-WASP) regulates reorganization of the actin cytoskeleton through activation of the Arp2/3 complex. Here, we show that heat shock protein 90 (HSP90) regulates N-WASP-induced actin polymerization in cooperation with phosphorylation of N-WASP. HSP90 binds directly to N-WASP, but binding alone does not affect the rate of N-WASP/Arp2/3 complex-induced in vitro actin polymerization. An Src family tyrosine kinase, v-Src, phosphorylates and activates N-WASP. HSP90 increases the phosphorylation of N-WASP by v-Src, leading to enhanced N-WASP-dependent actin polymerization. In addition, HSP90 protects phosphorylated and activated N-WASP from proteasome-dependent degradation, resulting in amplification of N-WASP-dependent actin polymerization. Association between HSP90 and N-WASP is increased in proportion to activation of N-WASP by phosphorylation. HSP90 is colocalized and associated with active N-WASP at podosomes in 3Y1/v-Src cells and at growing neurites in PC12 cells, whose actin structures are clearly inhibited by blocking the binding of HSP90 to N-WASP. These findings suggest that HSP90 induces efficient activation of N-WASP downstream of phosphorylation signal by Src family kinases and is critical for N-WASP-dependent podosome formation and neurite extension.
authors.affiliation: Department of Biochemistry, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
authors.forename: Sun Joo
authors.initials: SJ
authors.lastname: Park
authors.forename: Shiro
authors.initials: S
authors.lastname: Suetsugu
authors.forename: Tadaomi
authors.initials: T
authors.lastname: Takenawa
mesh_terms: D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D022081:Cell Surface Extensions / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004789:Enzyme Activation; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D015688:Oncogene Protein pp60(v-src) / Q000378:metabolism; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: C495926:ACTR2 protein, human; C495928:ACTR3 protein, human; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D003598:Cytoskeletal Proteins; D018841:HSP90 Heat-Shock Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; C495771:WASL protein, human; C495770:Wasl protein, rat; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D015688:Oncogene Protein pp60(v-src); D019061:src-Family Kinases; D046988:Proteasome Endopeptidase Complex