An active Src kinase-beta-actin association is linked to actin dynamics at the periphery of colon cancer cells

Exp Cell Res. 2007 Sep 10;313(15):3175-88. doi: 10.1016/j.yexcr.2007.04.037. Epub 2007 May 24.

Abstract

Src controls the dynamic actin cytoskeleton in fibroblasts and in cancer cells, although it is not known how direct its effects are. Using FRET/FLIM imaging, we found that wild type Src associates directly, or indirectly, with peripheral beta-actin at integrin adhesions after serum stimulation, and that an active Src kinase domain is essential. Beta-actin can be directly tyrosine-phosphorylated by Src in vitro, and in a Src-dependent manner in cells. Moreover, beta-actin dynamics are suppressed when Src is rendered kinase-inactive. Surprisingly, debilitating mutations in the Src SH2 or SH3 domains do not suppress association of Src with beta-actin. This may therefore be an example of a spatially regulated Src kinase/substrate interaction that is controlling peripheral actin dynamics. Interestingly, there is no FRET between Src and beta-actin at cadherin-mediated cell-cell contacts, despite apparent co-localization there, demonstrating precise spatial specificity of Src/beta-actin complexes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Actins / physiology*
  • Amino Acid Sequence
  • Cell Communication
  • Cell Line, Tumor
  • Colonic Neoplasms
  • Cytoskeletal Proteins / metabolism
  • Cytoskeleton / metabolism
  • Enzyme Activation
  • Fluorescence Resonance Energy Transfer
  • Humans
  • Molecular Sequence Data
  • Mutation
  • Phosphorylation
  • Protein Binding
  • Signal Transduction
  • src Homology Domains
  • src-Family Kinases / genetics
  • src-Family Kinases / metabolism*

Substances

  • Actins
  • Cytoskeletal Proteins
  • src-Family Kinases