A novel neural Wiskott-Aldrich syndrome protein (N-WASP) binding protein, WISH, induces Arp2/3 complex activation independent of Cdc42.
We identified a novel adaptor protein that contains a Src homology (SH)3 domain, SH3 binding proline-rich sequences, and a leucine zipper-like motif and termed this protein WASP interacting SH3 protein (WISH). WISH is expressed predominantly in neural tissues and testis. It bound Ash/Grb2 through its proline-rich regions and neural Wiskott-Aldrich syndrome protein (N-WASP) through its SH3 domain. WISH strongly enhanced N-WASP-induced Arp2/3 complex activation independent of Cdc42 in vitro, resulting in rapid actin polymerization. Furthermore, coexpression of WISH and N-WASP induced marked formation of microspikes in Cos7 cells, even in the absence of stimuli. An N-WASP mutant (H208D) that cannot bind Cdc42 still induced microspike formation when coexpressed with WISH. We also examined the contribution of WISH to a rapid actin polymerization induced by brain extract in vitro. Arp2/3 complex was essential for brain extract-induced rapid actin polymerization. Addition of WISH to extracts increased actin polymerization as Cdc42 did. However, WISH unexpectedly could activate actin polymerization even in N-WASP-depleted extracts. These findings suggest that WISH activates Arp2/3 complex through N-WASP-dependent and -independent pathways without Cdc42, resulting in the rapid actin polymerization required for microspike formation.
Fukuoka
M
M
Department of Biochemistry, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan.
Suetsugu
S
S
Miki
H
H
Fukami
K
K
Endo
T
T
Takenawa
T
T
D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D001923:Brain Chemistry; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D002460:Cell Line; D022081:Cell Surface Extensions / Q000378:metabolism; D016895:Culture Media, Serum-Free; D003598:Cytoskeletal Proteins; D051380:GRB2 Adaptor Protein; D017930:Genes, Reporter; D006801:Humans; D016350:Leucine Zippers; D008969:Molecular Sequence Data; D009124:Muscle Proteins; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011108:Polymers / Q000378:metabolism; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014923:Wiskott-Aldrich Syndrome; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism*; D018909:src Homology Domains
C495926:ACTR2 protein, human; C495928:ACTR3 protein, human; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D016895:Culture Media, Serum-Free; D003598:Cytoskeletal Proteins; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; C495950:Grb2 protein, rat; D009124:Muscle Proteins; C486062:NCKIPSD protein, human; C426229:Nckipsd protein, mouse; D009419:Nerve Tissue Proteins; D011108:Polymers; D011506:Proteins; D011993:Recombinant Fusion Proteins; C495771:WASL protein, human; C495770:Wasl protein, rat; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D020764:cdc42 GTP-Binding Protein