title: Palmitoylation regulates vesicular trafficking of R-Ras to membrane ruffles and effects on ruffling and cell spreading.
abstract: In this study we investigated the dynamics of R-Ras intracellular trafficking and its contributions to the unique roles of R-Ras in membrane ruffling and cell spreading. Wild type and constitutively active R-Ras localized to membranes of both Rab11- and transferrin-positive and -negative vesicles, which trafficked anterograde to the leading edge in migrating cells. H-Ras also co-localized with R-Ras in many of these vesicles in the vicinity of the Golgi, but R-Ras and H-Ras vesicles segregated proximal to the leading edge, in a manner dictated by the C-terminal membrane-targeting sequences. These segregated vesicle trafficking patterns corresponded to distinct modes of targeting to membrane ruffles at the leading edge. Geranylgeranylation was required for membrane anchorage of R-Ras, whereas palmitoylation was required for exit from the Golgi in post-Golgi vesicle membranes and trafficking to the plasma membrane. R-Ras vesicle membranes did not contain phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P(3)), whereas R-Ras co-localized with PtdIns(3,4,5)P(3) in membrane ruffles. Finally, palmitoylation-deficient R-Ras blocked membrane ruffling, R-Ras/PI3-kinase interaction, enrichment of PtdIns(3,4,5)P(3) at the plasma membrane, and R-Ras-dependent cell spreading. Thus, lipid modification of R-Ras dictates its vesicle trafficking, targeting to membrane ruffles, and its unique roles in localizing PtdIns(3,4,5)P(3) to ruffles and promoting cell spreading.
authors: Department of Anatomy & Cell Biology, The Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA, USA.
authors: Jeremy G T
authors: JG
authors: Wurtzel
authors: Puneet
authors: P
authors: Kumar
authors: Lawrence E
authors: LE
authors: Goldfinger
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D006056:Golgi Apparatus / Q000378:metabolism; D054878:Lipoylation; D051379:Mice; D041681:NIH 3T3 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates / Q000032:analysis / Q000378:metabolism; D021381:Protein Transport; D022161:Transport Vesicles / Q000378:metabolism*; D018631:ras Proteins / Q000032:analysis* / Q000378:metabolism*
chemical_list: D018129:Phosphatidylinositol Phosphates; C060974:phosphatidylinositol 3,4,5-triphosphate; D019869:Phosphatidylinositol 3-Kinases; C513254:Rras protein, mouse; D018631:ras Proteins