A complex of N-WASP and WIP integrates signalling cascades that lead to actin polymerization.

:Wiskott-Aldrich syndrome protein (WASP) and N-WASP have emerged as key proteins connecting signalling cascades to actin polymerization. Here we show that the amino-terminal WH1 domain, and not the polyproline-rich region, of N-WASP is responsible for its recruitment to sites of actin polymerization during Cdc42-independent, actin-based motility of vaccinia virus. Recruitment of N-WASP to vaccinia is mediated by WASP-interacting protein (WIP), whereas in Shigella WIP is recruited by N-WASP. Our observations show that vaccinia and Shigella activate the Arp2/3 complex to achieve actin-based motility, by mimicking either the SH2/SH3-containing adaptor or Cdc42 signalling pathways to recruit the N-WASP-WIP complex. We propose that the N-WASP-WIP complex has a pivotal function in integrating signalling cascades that lead to actin polymerization.

Moreau V ，Frischknecht F ，Reckmann I ，Vincentelli R ，Rabut G ，Stewart D ，Way M ... -  《NATURE CELL BIOLOGY》

WIP provides an essential link between Nck and N-WASP during Arp2/3-dependent actin polymerization.

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.

Donnelly SK ，Weisswange I ，Zettl M ，Way M ... -  《-》

Phosphatidylinositol 4,5-biphosphate (PIP2)-induced vesicle movement depends on N-WASP and involves Nck, WIP, and Grb2.

Benesch S ，Lommel S ，Steffen A ，Stradal TE ，Scaplehorn N ，Way M ，Wehland J ，Rottner K ... -  《JOURNAL OF BIOLOGICAL CHEMISTRY》

A novel neural Wiskott-Aldrich syndrome protein (N-WASP) binding protein, WISH, induces Arp2/3 complex activation independent of Cdc42.

Fukuoka M ，Suetsugu S ，Miki H ，Fukami K ，Endo T ，Takenawa T ... -  《-》

WIP regulates N-WASP-mediated actin polymerization and filopodium formation.

Martinez-Quiles N ，Rohatgi R ，Antón IM ，Medina M ，Saville SP ，Miki H ，Yamaguchi H ，Takenawa T ，Hartwig JH ，Geha RS ，Ramesh N ... -  《NATURE CELL BIOLOGY》