Coordinate activation of c-Src by SH3- and SH2-binding sites on a novel p130Cas-related protein, Sin

Genes Dev. 1996 Jun 1;10(11):1341-55. doi: 10.1101/gad.10.11.1341.

Abstract

To understand how protein-protein interactions mediated by the Src-SH3 domain affect c-Src signaling, we screened for proteins that interact with the Src-SH3. We found a novel protein, Sin (Src interacting or signal integrating protein), that binds to Src-SH3 with high affinity, contains numerous tyrosine residues in configurations suggestive of SH2-binding sites, and is related to the v-Src substrate p130Cas. In cotransfection assays, a small fragment of Sin retaining the Src-SH3-binding site and one tyrosine-containing motif induced c-Src activation as measured by a transcriptional reporter. Phosphorylation of the peptide on tyrosine by c-Src, as a consequence of Src-SH3 binding, was necessary for its stable interaction with c-Src in vivo and for transcriptional activation. Phosphorylation of multiple tyrosine-containing motifs found on Sin correlated with c-Crk and cellular phosphoprotein binding to Sin as well as increased c-Src activity. These data suggest that (1) SH2 and SH3 ligand sites on Sin cooperatively activate the signaling potential of c-Src, (2) Sin acts as both an activator and a substrate for c-Src, and (3) phosphorylated Sin may serve as a signaling effector molecule for Src by binding to multiple cellular proteins.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Cell Adhesion
  • Cell Line
  • Humans
  • Molecular Sequence Data
  • Peptides / genetics
  • Peptides / metabolism
  • Phosphorylation
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-cbl
  • Proto-Oncogene Proteins pp60(c-src) / metabolism*
  • Signal Transduction
  • Ubiquitin-Protein Ligases*
  • src Homology Domains*

Substances

  • Peptides
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-cbl
  • Ubiquitin-Protein Ligases
  • Proto-Oncogene Proteins pp60(c-src)
  • CBL protein, human