Recruitment of the Arp2/3 complex to vinculin: coupling membrane protrusion to matrix adhesion

J Cell Biol. 2002 Dec 9;159(5):881-91. doi: 10.1083/jcb.200206043. Epub 2002 Dec 9.

Abstract

Cell migration involves many steps, including membrane protrusion and the development of new adhesions. Here we have investigated whether there is a link between actin polymerization and integrin engagement. In response to signals that trigger membrane protrusion, the actin-related protein (Arp)2/3 complex transiently binds to vinculin, an integrin-associated protein. The interaction is regulated, requiring phosphatidylinositol-4,5-bisphosphate and Rac1 activation, and is sufficient to recruit the Arp2/3 complex to new sites of integrin aggregation. Binding of the Arp2/3 complex to vinculin is direct and does not depend on the ability of vinculin to associate with actin. We have mapped the binding site for the Arp2/3 complex to the hinge region of vinculin, and a point mutation in this region selectively blocks binding to the Arp2/3 complex. Compared with WT vinculin, expression of this mutant in vinculin-null cells results in diminished lamellipodial protrusion and spreading on fibronectin. The recruitment of the Arp2/3 complex to vinculin may be one mechanism through which actin polymerization and membrane protrusion are coupled to integrin-mediated adhesion.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 3T3 Cells
  • Actin-Related Protein 2
  • Actin-Related Protein 3
  • Actins / metabolism
  • Androstadienes / pharmacology
  • Animals
  • Binding Sites / genetics
  • Cell Adhesion*
  • Cell Line
  • Cell Movement
  • Cells, Cultured
  • Cytoskeletal Proteins / metabolism*
  • Embryo, Mammalian
  • Epidermal Growth Factor / pharmacology
  • Extracellular Matrix / metabolism
  • Fibronectins / physiology
  • Green Fluorescent Proteins
  • HeLa Cells
  • Humans
  • Integrins / metabolism
  • Luminescent Proteins / metabolism
  • Mice
  • Phosphatidylinositol 3-Kinases / pharmacology
  • Phosphoinositide-3 Kinase Inhibitors
  • Point Mutation
  • Protein Binding
  • Pseudopodia / metabolism*
  • Recombinant Fusion Proteins / metabolism
  • Vinculin / antagonists & inhibitors
  • Vinculin / chemistry
  • Vinculin / genetics
  • Vinculin / metabolism*
  • Wortmannin
  • rac1 GTP-Binding Protein / metabolism

Substances

  • ACTR2 protein, human
  • ACTR3 protein, human
  • Actin-Related Protein 2
  • Actin-Related Protein 3
  • Actins
  • Actr2 protein, mouse
  • Actr3 protein, mouse
  • Androstadienes
  • Cytoskeletal Proteins
  • Fibronectins
  • Integrins
  • Luminescent Proteins
  • Phosphoinositide-3 Kinase Inhibitors
  • Recombinant Fusion Proteins
  • Vinculin
  • Green Fluorescent Proteins
  • Epidermal Growth Factor
  • rac1 GTP-Binding Protein
  • Wortmannin