Abstract
Induction of filopodia is dependent on activation of the small GTPase Cdc42 and on neural Wiskott-Aldrich-syndrome protein (N-WASP). Here we show that WASP-interacting protein (WIP) interacts directly with N-WASP and actin. WIP retards N-WASP/Cdc42-activated actin polymerization mediated by the Arp2/3 complex, and stabilizes actin filaments. Microinjection of WIP into NIH 3T3 fibroblasts induces filopodia; this is inhibited by microinjection of anti-N-WASP antibody. Microinjection of anti-WIP antibody inhibits induction of filopodia by bradykinin, by an active Cdc42 mutant (Cdc42(V12)) and by N-WASP. Our results indicate that WIP and N-WASP may act as a functional unit in filopodium formation, which is consistent with their role in actin-tail formation in cells infected with vaccinia virus or Shigella.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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3T3 Cells
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Actin-Related Protein 2
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Actin-Related Protein 3
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Actins / metabolism*
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Animals
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Blotting, Western
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Bradykinin / pharmacology
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Carrier Proteins / metabolism*
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Cell Line
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Cytoskeletal Proteins*
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Dose-Response Relationship, Drug
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Electrophoresis, Polyacrylamide Gel
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Enzyme Activation
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Glutathione Transferase / metabolism
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Mice
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Microscopy, Fluorescence
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Mutation
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Nerve Tissue Proteins / metabolism*
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Protein Binding
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Protein Structure, Tertiary
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Pseudopodia / metabolism*
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Rabbits
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Recombinant Fusion Proteins / metabolism
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Recombinant Proteins / metabolism
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Shigella / metabolism
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Signal Transduction
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Time Factors
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Two-Hybrid System Techniques
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Wiskott-Aldrich Syndrome Protein, Neuronal
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cdc42 GTP-Binding Protein / metabolism
Substances
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Actin-Related Protein 2
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Actin-Related Protein 3
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Actins
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Actr2 protein, mouse
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Actr3 protein, mouse
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Carrier Proteins
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Cytoskeletal Proteins
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Nerve Tissue Proteins
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Recombinant Fusion Proteins
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Recombinant Proteins
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Wasl protein, mouse
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Waspip protein, mouse
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Wiskott-Aldrich Syndrome Protein, Neuronal
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Glutathione Transferase
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cdc42 GTP-Binding Protein
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Bradykinin