Dominant-negative Caveolin Inhibits H-Ras Function by Disrupting Cholesterol-Rich Plasma Membrane Domains

Nat Cell Biol. 1999 Jun;1(2):98-105. doi: 10.1038/10067.

Abstract

The plasma membrane pits known as caveolae have been implicated both in cholesterol homeostasis and in signal transduction. CavDGV and CavKSY, two dominant-negative amino-terminal truncation mutants of caveolin, the major structural protein of caveolae, significantly inhibited caveola-mediated SV40 infection, and were assayed for effects on Ras function. We find that CavDGV completely blocked Raf activation mediated by H-Ras, but not that mediated by K-Ras. Strikingly, the inhibitory effect of CavDGV on H-Ras signalling was completely reversed by replenishing cell membranes with cholesterol and was mimicked by cyclodextrin treatment, which depletes membrane cholesterol. These results provide a crucial link between the cholesterol-trafficking role of caveolin and its postulated role in signal transduction through cholesterol-rich surface domains. They also provide direct evidence that H-Ras and K-Ras, which are targeted to the plasma membrane by different carboxy-terminal anchors, operate in functionally distinct microdomains of the plasma membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Animals
  • Caveolin 1
  • Caveolins*
  • Cell Line
  • Cell Membrane / physiology*
  • Chlorocebus aethiops
  • Cholesterol / metabolism*
  • Cricetinae
  • Genetic Vectors
  • Membrane Lipids / metabolism*
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism*
  • Mice
  • Proto-Oncogene Proteins p21(ras) / antagonists & inhibitors
  • Proto-Oncogene Proteins p21(ras) / metabolism*
  • Recombinant Proteins / metabolism
  • Sequence Deletion*
  • Signal Transduction
  • Simian virus 40
  • Transfection

Substances

  • Cav1 protein, mouse
  • Caveolin 1
  • Caveolins
  • Membrane Lipids
  • Membrane Proteins
  • Recombinant Proteins
  • Cholesterol
  • Proto-Oncogene Proteins p21(ras)