title: WIP provides an essential link between Nck and N-WASP during Arp2/3-dependent actin polymerization.
abstract: Nck links phosphotyrosine-based signaling to Arp2/3-dependent actin polymerization during many different cellular processes as well as actin-based motility of enteropathogenic Escherichia coli (EPEC), vaccinia, and other vertebrate poxviruses by interacting with N-WASP/WASP. Nck also binds WASP-interacting protein (WIP), which inhibits the ability of N-WASP to activate the Arp2/3 complex until it receives an appropriate signaling input. Using mouse embryonic fibroblasts (MEFs) lacking Nck, WIP, or N-WASP, we have investigated whether an interaction of Nck with both WIP and N-WASP is required for their recruitment to vaccinia during Arp2/3-dependent actin assembly. We find that WIP or its homolog WIRE is required for N-WASP recruitment and actin-based motility of the virus. WIP contains two Nck-binding sites and is recruited to the virus, bound to N-WASP, by interacting with the second SH3 domain of Nck. N-WASP also contains two Nck-binding sites, but its recruitment is dependent on its interaction with WIP rather than Nck. The first and third SH3 domains of Nck are not required to recruit the WIP:N-WASP complex but are essential to stimulate actin assembly. We have established that WIP acts as an essential link between Nck and N-WASP. Our observations provide important insights into the hierarchy and connections in one of the major cellular signaling networks stimulating Arp2/3 complex-dependent actin polymerization.
authors.affiliation: Cell Motility Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
authors.forename: Sara K
authors.initials: SK
authors.lastname: Donnelly
authors.forename: Ina
authors.initials: I
authors.lastname: Weisswange
authors.forename: Markus
authors.initials: M
authors.lastname: Zettl
authors.forename: Michael
authors.initials: M
authors.lastname: Way
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism*; D000199:Actins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D005347:Fibroblasts; D051379:Mice; D015513:Oncogene Proteins / Q000378:metabolism*; D019000:Phosphotyrosine / Q000378:metabolism; D058105:Polymerization; D011485:Protein Binding; D015398:Signal Transduction; D014616:Vaccinia virus / Q000378:metabolism*; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal / Q000378:metabolism*; D018909:src Homology Domains
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; C078332:Nck protein; D015513:Oncogene Proteins; C495772:Wasl protein, mouse; C491671:Waspip protein, mouse; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D019000:Phosphotyrosine