Article abstract
Nature Cell Biology 1, 98 - 105 (1999)
Published online: 15 May 1999 | doi:10.1038/10067
Dominant-negative caveolin inhibits H-Ras function by disrupting cholesterol-rich plasma membrane domains
Sandrine Roy1, Robert Luetterforst2, Angus Harding1, Ann Apolloni1, Maria Etheridge1, Espen Stang2,3, Barbara Rolls2, John F. Hancock1 & Robert G. Parton2
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.
- Queensland Cancer Fund Laboratory of Experimental Oncology, Department of Pathology, University of Queensland Medical School, Herston Road, Brisbane 4006, Australia
- Centre for Microscopy and Microanalysis, Centre for Molecular and Cellular Biology, Department of Physiology and Pharmacology, University of Queensland, Brisbane 4072, Australia
- Current address: Institute of Pathology, The National Hospital, Oslo 0027, Norway
Correspondence to: John F. Hancock1 e-mail: j.hancock@mailbox.uq.edu.au
