Activated K-Ras and H-Ras display different interactions with saturable nonraft sites at the surface of live cells.

摘要: Ras–membrane interactions play important roles in signaling and oncogenesis. H-Ras K-Ras have nonidentical membrane anchoring moieties that can direct them to different compartments. Ras–lipid raft were reported, but recent studies suggest activated are not resident. However, specific of Ras proteins with nonraft sites, which may underlie functional differences phenotypic variation between isoforms, unexplored. Here we used lateral mobility by FRAP investigate the green fluorescent protein–tagged H- live cells. All isoforms displayed stable association, moving diffusion exchange a cytoplasmic pool. The rates constitutively active K- increased their expression levels saturable manner, suggesting dynamic association sites or domains. These distinct from lipid rafts, as mutants Moreover, they appear be for K-Ras. wild-type H-Ras, only isoform preferentially localized cholesterol-sensitive rafts independent its level. Our findings provide mechanism selective isoforms.