IGF-I induced rapid recruitment of integrin beta1 to lipid rafts is Caveolin-1 dependent

Biochem Biophys Res Commun. 2009 Mar 13;380(3):489-92. doi: 10.1016/j.bbrc.2009.01.102. Epub 2009 Jan 23.

Abstract

Caveolin-1 (Cav-1) regulates both insulin like growth factor receptor (IGF-IR) and integrin beta1 function. However, the role of Cav-1 in IGF-IR/integrin beta1 cross talk remains to be established. In this study, we observed that IGF-I did not induce integrin beta1 internalization but its plasma membrane reorganization. In particular, we found a rapid and transient association between integrin beta1 and Cav-1 followed by the enrichment of integrin beta1 in lipid rafts. To determine the role of Cav-1 in this process, we transfected Hacat cells with small interfering RNA specific for Cav-1 (siRNA-Cav-1) and with a scrambled siRNA as control (siRNA-Ctr). Cav-1 down regulated Hacat cells were then stimulated with IGF-I and analyzed by immunofluorescence and flow cytometry. We found that Cav-1 silencing abolished the recruitment of integrin beta1 to lipid rafts in the presence of IGF-I. These data demonstrate that IGF-IR/integrin beta1 cross talk is followed by integrin beta1 lipid raft compartmentalization and that Cav-1 is required for this process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caveolin 1 / genetics
  • Caveolin 1 / metabolism*
  • Cell Line
  • Humans
  • Immunoprecipitation
  • Insulin-Like Growth Factor I / metabolism*
  • Integrin beta1 / metabolism*
  • Membrane Microdomains / metabolism*
  • RNA, Small Interfering / genetics
  • Transfection

Substances

  • CAV1 protein, human
  • Caveolin 1
  • Integrin beta1
  • RNA, Small Interfering
  • Insulin-Like Growth Factor I