The Abl/Arg substrate ArgBP2/nArgBP2 coordinates the function of multiple regulatory mechanisms converging on the actin cytoskeleton

Proc Natl Acad Sci U S A. 2005 Feb 1;102(5):1731-6. doi: 10.1073/pnas.0409376102. Epub 2005 Jan 19.

Abstract

ArgBP2, and its brain-specific splice variant, nArgBP2, are interactors and substrates of Abl/Arg tyrosine kinases and of the ubiquitin ligase Cbl. They are members of a family of adaptor proteins that colocalize with actin on stress fibers and at cell-adhesion sites, including neuronal synapses. We show here that their NH2-terminal region, which contains a sorbin homology domain domain, interacts with spectrin, and we identify binding proteins for their COOH-terminal SH3 domains. All these binding partners participate in the regulation of the actin cytoskeleton. These include dynamin, synaptojanin, and WAVE isoforms, as well as WAVE regulatory proteins. At least two of the ArgBP2/nArgBP2 binding partners, synaptojanin 2B and WAVE2, undergo ubiquitination and Abl-dependent tyrosine phosphorylation. ArgBP2/nArgBP2 knockdown in astrocytes produces a redistribution of focal adhesion proteins and an increase in peripheral actin ruffles, whereas nArgBP2 overexpression produces a collapse of the actin cytoskeleton. Thus, ArgBP2/nArgBP2 is a scaffold protein that control the balance between adhesion and motility by coordinating the function of multiple signaling pathways converging on the actin cytoskeleton.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / metabolism*
  • Adaptor Proteins, Signal Transducing
  • Animals
  • CHO Cells
  • Cell Adhesion / physiology
  • Cricetinae
  • Cytoskeleton / physiology*
  • Genes, myc
  • Homeodomain Proteins / chemistry
  • Homeodomain Proteins / metabolism*
  • Microscopy, Video
  • Phosphotyrosine / metabolism
  • Rats
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / metabolism
  • Synapses / physiology
  • src Homology Domains

Substances

  • Actins
  • Adaptor Proteins, Signal Transducing
  • Homeodomain Proteins
  • Recombinant Fusion Proteins
  • Sorbs2 protein, rat
  • Phosphotyrosine