title: The rate of N-WASP exchange limits the extent of ARP2/3-complex-dependent actin-based motility.
abstract: Understanding cell motility will require detailed knowledge not only of the localization of signalling networks regulating actin polymerization, but also of their dynamics. Unfortunately, many signalling networks are not amenable to such analysis, as they are frequently transient and dispersed. By contrast, the signalling pathways used by pathogens undergoing actin-based motility are highly localized and operate in a constitutive fashion. Taking advantage of this, we have analysed the dynamics of neuronal Wiskott-Aldrich syndrome protein (N-WASP), WASP-interacting protein (WIP), GRB2 and NCK, which are required to stimulate actin-related protein (ARP)2/3-complex-dependent actin-based motility of vaccinia virus, using fluorescence recovery after photobleaching. Here we show that all four proteins are rapidly exchanging, albeit at different rates, and that the turnover of N-WASP depends on its ability to stimulate ARP2/3-complex-mediated actin polymerization. Conversely, disruption of the interaction of N-WASP with GRB2 and/or the barbed ends of actin filaments increases its exchange rate and results in a faster rate of virus movement. We suggest that the exchange rate of N-WASP controls the rate of ARP2/3-complex-dependent actin-based motility by regulating the extent of actin polymerization by antagonizing filament capping.
authors.affiliation: Cell Motility Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3PX, UK.
authors.forename: Ina
authors.initials: I
authors.lastname: Weisswange
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Newsome
authors.forename: Sibylle
authors.initials: S
authors.lastname: Schleich
authors.forename: Michael
authors.initials: M
authors.lastname: Way
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism*; D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing; D001704:Biopolymers / Q000737:chemistry / Q000378:metabolism; D002460:Cell Line; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism; D051380:GRB2 Adaptor Protein / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D014616:Vaccinia virus / Q000235:genetics; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal / Q000235:genetics / Q000378:metabolism*
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D001704:Biopolymers; D003598:Cytoskeletal Proteins; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D047908:Intracellular Signaling Peptides and Proteins; C078332:Nck protein; D015513:Oncogene Proteins; C109903:WIPF1 protein, human; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal