Abstract
Although small GTP-binding proteins of the Rho family have been implicated in signaling to the actin cytoskeleton, the exact nature of the linkage has remained obscure. We describe a novel mechanism that links one Rho family member, Cdc42, to actin polymerization. N-WASP, a ubiquitously expressed Cdc42-interacting protein, is required for Cdc42-stimulated actin polymerization in Xenopus egg extracts. The C terminus of N-WASP binds to the Arp2/3 complex and dramatically stimulates its ability to nucleate actin polymerization. Although full-length N-WASP is less effective, its activity can be greatly enhanced by Cdc42 and phosphatidylinositol (4,5) bisphosphate. Therefore, N-WASP and the Arp2/3 complex comprise a core mechanism that directly connects signal transduction pathways to the stimulation of actin polymerization.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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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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Biopolymers / metabolism
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Cattle
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Cell Cycle Proteins / metabolism*
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Cytoskeletal Proteins*
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Female
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GTP-Binding Proteins / metabolism*
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In Vitro Techniques
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Macromolecular Substances
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Models, Biological
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Nerve Tissue Proteins / chemistry
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism*
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Oocytes / metabolism
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Peptide Fragments / chemistry
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Peptide Fragments / genetics
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Peptide Fragments / metabolism
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Phosphatidylinositol 4,5-Diphosphate / metabolism
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Rats
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Signal Transduction
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Wiskott-Aldrich Syndrome Protein, Neuronal
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Xenopus
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cdc42 GTP-Binding Protein
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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Biopolymers
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Cell Cycle Proteins
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Cytoskeletal Proteins
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Macromolecular Substances
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Nerve Tissue Proteins
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Peptide Fragments
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Phosphatidylinositol 4,5-Diphosphate
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Recombinant Proteins
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Wasl protein, rat
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Wiskott-Aldrich Syndrome Protein, Neuronal
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GTP-Binding Proteins
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cdc42 GTP-Binding Protein