title: Two verprolin homology domains increase the Arp2/3 complex-mediated actin polymerization activities of N-WASP and WAVE1 C-terminal regions.
abstract: WASP family proteins induce actin polymerization through a C-terminal verprolin homology, cofilin homology, and acidic (VCA) region by activating the Arp2/3 complex. The N-WASP VCA region is the most potent activator of the Arp2/3 complex. In addition, full-length WAVE1 and a WAVE1 VCA fragment show differential activity. The mechanisms underlying these differences are poorly understood. We examined the activities of various N-WASP and WAVE1 VCA mutant proteins with several types of fusion moieties. When fused to GST, maltose-binding protein, or the WAVE1 proline-rich domain, N-WASP VCA and WAVE1 VCA mutant proteins with two V motifs showed stronger activities than wild-type WAVE1 VCA with one V motif, demonstrating the importance of two V motifs for strong VCA activity. A WAVE1 VCA fragment tagged with six histidines (His) showed markedly reduced activity compared to GST-fused VCA, whereas His-tagged N-WASP VCA showed similar activity to GST-fused VCA. An additional V motif failed to enhance WAVE1 VCA activity in the His-tagged form. Thus, the WAVE1 VCA fragment may exist in an unfavorable conformation to activate the Arp2/3 complex, implying the existence of a structural difference between WAVE1 and N-WASP VCAs in addition to the number of V motifs.
authors.affiliation: Division of Cancer Genomics, Institute of Medical Science, University of Tokyo, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Miki
authors.forename: Tadaomi
authors.initials: T
authors.lastname: Takenawa
mesh_terms: D051377:Actin-Related Protein 2; D000199:Actins / Q000378:metabolism*; D020816:Amino Acid Motifs; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D008840:Microfilament Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D014923:Wiskott-Aldrich Syndrome; D051300:Wiskott-Aldrich Syndrome Protein Family; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal
chemical_list: D051377:Actin-Related Protein 2; D000199:Actins; D003598:Cytoskeletal Proteins; D005656:Fungal Proteins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C090350:VRP1 protein, S cerevisiae; D051300:Wiskott-Aldrich Syndrome Protein Family; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal