p190-B, a new member of the Rho GAP family, and Rho are induced to cluster after integrin cross-linking

J Biol Chem. 1995 Dec 29;270(52):30919-26. doi: 10.1074/jbc.270.52.30919.


p120GAP forms distinct complexes with two phosphoproteins, p62 and p190. Here we have cloned a cDNA encoding a protein with 51% amino acid identity to p190 (hereafter designated p190-A) and have designated it p190-B. The N-terminal portion of p190-B contained several motifs characteristic of a GTPase domain, while its C terminus contained a Rho GAP domain. A recombinant Rho GAP domain polypeptide showed GAP activity for RhoA, Rac1, and G25K/CDC42Hs. Immunoprecipitation and immunofluorescence studies demonstrated that p190-B protein was expressed in a variety of cells and was localized diffusely in the cytoplasm and in fibrillar patterns that co-localized with the alpha 5 beta 1 integrin receptor for fibronectin. Adhesion of fibronectin-coated latex beads to cells resulted in recruitment of significant amounts of p190-B and Rho to the plasma membrane beneath the site of bead binding. In contrast, beads coated with polylysine or concanavalin A were unable to recruit p190-B or Rho. Additionally, anti-beta 1 or anti-alpha 5 integrin antibody-coated beads were also able to recruit large amounts of p190-B and Rho. These results identify a novel second member of the p190 family and establish the existence of a novel transmembrane link between integrins and a new protein p190-B and Rho.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cloning, Molecular
  • Fibronectins / metabolism
  • GTP-Binding Proteins / metabolism*
  • GTPase-Activating Proteins
  • Guanine Nucleotide Exchange Factors*
  • Humans
  • Integrins / metabolism*
  • Molecular Sequence Data
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Protein Binding
  • Proteins / metabolism*
  • Repressor Proteins
  • Sequence Homology, Amino Acid
  • rhoA GTP-Binding Protein


  • ARHGAP35 protein, human
  • ARHGAP5 protein, human
  • Fibronectins
  • GTPase-Activating Proteins
  • Guanine Nucleotide Exchange Factors
  • Integrins
  • Nuclear Proteins
  • Phosphoproteins
  • Proteins
  • Repressor Proteins
  • GTP-Binding Proteins
  • rhoA GTP-Binding Protein

Associated data

  • GENBANK/U17032