title: A chemical inhibitor of N-WASP reveals a new mechanism for targeting protein interactions.
abstract: Cell morphology and motility are governed largely by complex signaling networks that ultimately engage the actin cytoskeleton. Understanding how individual circuits contribute to the process of forming cellular structures would be aided greatly by the availability of specific chemical inhibitors. We have used a novel chemical screen in Xenopus cell-free extracts to identify compounds that inhibit signaling pathways regulating actin polymerization. Here we report the results of a high-throughput screen for compounds that inhibit phosphatidylinositol 4,5-bisphosphate (PIP(2))-induced actin assembly and the identification of the first compound, a cyclic peptide, known to block actin assembly by inhibiting an upstream signaling component. We identify the target of this compound as N-WASP, a protein that has been investigated for its role as a node interconnecting various actin signaling networks. We show that this compound prevents activation of the Arp2/3 complex by N-WASP by allosterically stabilizing the autoinhibited conformation of N-WASP.
authors.affiliation: Department of Cell Biology and the Institute for Chemistry and Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Peterson
authors.forename: R S
authors.initials: RS
authors.lastname: Lokey
authors.forename: T J
authors.initials: TJ
authors.lastname: Mitchison
authors.forename: M W
authors.initials: MW
authors.lastname: Kirschner
mesh_terms: D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins / Q000378:metabolism; D000818:Animals; D003598:Cytoskeletal Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors*; D010456:Peptides, Cyclic / Q000378:metabolism* / Q000494:pharmacology; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D011108:Polymers; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D014982:Xenopus laevis; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism
chemical_list: D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D003598:Cytoskeletal Proteins; D009419:Nerve Tissue Proteins; D010456:Peptides, Cyclic; D019269:Phosphatidylinositol 4,5-Diphosphate; D011108:Polymers; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; C437887:peptide 187-1; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D020764:cdc42 GTP-Binding Protein