Localization of epidermal growth factor-stimulated Ras/Raf-1 interaction to caveolae membrane

Chieko Mineo, Guy L. James, Eric J. Smart, Richard G W Anderson

Research output: Contribution to journalArticle

394 Scopus citations

Abstract

An essential step in the epidermal growth factor (EGF)dependent activation of MAP kinase is the recruitment of Raf-1 to the plasma membrane. Here we present evidence that caveolae are the membrane site where Raf-1 is recruited. Caveolae fractions prepared from normal Rat-1 cells grown in the absence of serum were highly enriched in both EGF receptors and Ras. Thirty seconds after EGF was added to these cells Raf-1 began to appear in caveolae but not in non-caveolae membrane fractions. The maximum concentration was reached at 3 min followed by a decline over the next 60 min. During this time EGF receptors disappeared from the caveolae fraction while the concentration of Ras remained constant. The Raf-1 in this fraction was able to phosphorylate MAP kinase kinase, whereas cytoplasmic Raf-1 in the same cell was inactive. Elevation of cellular cAMP blocked the recruitment of Raf-1 to caveolae. Overexpression of HaRas(V12) caused the recruitment of Raf-1 to caveolae independently of EGF stimulation, and this was blocked by the farnesyltransferase inhibitor BZA-5B. Finally, prenylation appeared to be required for localization of Ras to caveolae.

Original languageEnglish (US)
Pages (from-to)11930-11935
Number of pages6
JournalJournal of Biological Chemistry
Volume271
Issue number20
DOIs
StatePublished - Jun 3 1996

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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