Three separable domains regulate GTP-dependent association of H-ras with the plasma membrane

Barak Rotblat, Ian A. Prior, Cornelia Muncke, Robert G. Parton, Yoel Kloog, Yoav I. Henis, John F. Hancock

Research output: Contribution to journalArticlepeer-review

135 Scopus citations


The microlocalization of Ras proteins to different microdomains of the plasma membrane is critical for signaling specificity. Here we examine the complex membrane interactions of H-ras with a combination of FRAP on live cells to measure membrane affinity and electron microscopy of intact plasma membrane sheets to spatially map microdomains. We show that three separable forces operate on H-ras at the plasma membrane. The lipid anchor, comprising a processed CAAX motif and two palmitic acid residues, generates one attractive force that provides a high-affinity interaction with lipid rafts. The adjacent hypervariable linker domain provides a second attractive force but for nonraft plasma membrane microdomains. Operating against the attractive interaction of the lipid anchor for lipid rafts is a repulsive force generated by the N-terminal catalytic domain that increases when H-ras is GTP loaded. These observations lead directly to a novel mechanism that explains how H-ras lateral segregation is regulated by activation state: GTP loading decreases H-ras affinity for lipid rafts and allows the hypervariable linker domain to target to nonraft microdomains, the primary site of H-ras signaling.

Original languageEnglish
Pages (from-to)6799-6810
Number of pages12
JournalMolecular and Cellular Biology
Issue number15
StatePublished - 1 Aug 2004
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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