title: Association of mouse actin-binding protein 1 (mAbp1/SH3P7), an Src kinase target, with dynamic regions of the cortical actin cytoskeleton in response to Rac1 activation.
abstract: Yeast Abp1p is a cortical actin cytoskeleton protein implicated in cytoskeletal regulation, endocytosis, and cAMP-signaling. We have identified a gene encoding a mouse homologue of Abp1p, and it is identical to SH3P7, a protein shown recently to be a target of Src tyrosine kinases. Yeast and mouse Abp1p display the same domain structure including an N-terminal actin-depolymerizing factor homology domain and a C-terminal Src homology 3 domain. Using two independent actin-binding domains, mAbp1 binds to actin filaments with a 1:5 saturation stoichiometry. In stationary cells, mAbp1 colocalizes with cortical F-actin in fibroblast protrusions that represent sites of cellular growth. mAbp1 appears at the actin-rich leading edge of migrating cells. Growth factors cause mAbp1 to rapidly accumulate in lamellipodia. This response can be mimicked by expression of dominant-positive Rac1. mAbp1 recruitment appears to be dependent on de novo actin polymerization and occurs specifically at sites enriched for the Arp2/3 complex. mAbp1 is a newly identified cytoskeletal protein in mice and may serve as a signal-responsive link between the dynamic cortical actin cytoskeleton and regions of membrane dynamics.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720-3202, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: Kessels
authors.forename: A E
authors.initials: AE
authors.lastname: Engqvist-Goldstein
authors.forename: D G
authors.initials: DG
authors.lastname: Drubin
mesh_terms: D016475:3T3 Cells; D000199:Actins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002455:Cell Division; D002460:Cell Line; D002465:Cell Movement; D003599:Cytoskeleton; D004705:Endocytosis; D006801:Humans; D007424:Intracellular Fluid / Q000378:metabolism; D051379:Mice; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011108:Polymers; D012333:RNA, Messenger; D017421:Sequence Analysis; D013194:Staining and Labeling; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*; D018909:src Homology Domains; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D000199:Actins; C117063:DBNL protein, human; C485512:Dbnl protein, mouse; D008840:Microfilament Proteins; D010982:Platelet-Derived Growth Factor; D011108:Polymers; D012333:RNA, Messenger; D019061:src-Family Kinases; D020830:rac1 GTP-Binding Protein; D013755:Tetradecanoylphorbol Acetate