title: Interaction of shrimp ras protein with mammalian caveolin-1.
abstract: BALB/3T3 cells were transformed by transfection with DNA encoding the mutated ras(Q(61)K) from shrimp Penaeus japonicus (Huang and Chuang. 1999. J Exp Zool 283:510-521). The caveolin-1 in the membrane fraction extractable with 2% octyl glucoside was significant reduced, compared to untransformed cells. To understand this in more detail, the interaction of S-Ras with caveolin was investigated using caveolin-1 purified from rat lungs. The purified caveolin-1 binds c-Src, suppressing its autophosphorylation. It also binds to phosphatidylserine-cholesterol liposomes. These reconstituted caveolin-phosphatidylserine-cholesterol vesicles, which act as a model of caveolae, recruit both bacterially expressed S-Ras and rat K(B)-Ras proteins, as demonstrated on western blots with antibodies against caveolin-1 and Ras. Caveolin-1 suppressed the intrinsic GTPase activity of S-Ras, sustaining it in the active GTP bound form. By contrast, caveolin-1 enhanced the intrinsic GTPase activity of K(B)-Ras, to convert it into the inactive GDP-bound form. These events suggest that caveolin may act as a docking site for Ras proteins and may be able to either maintain or alter their activity state. These events may be associated with the ability of S-ras(Q(61)K) to successfully transform cells.
authors.affiliation: Division of Biochemistry and Molecular Sciences, Institute of Zoology, Academia Sinica, Nankang, Taipei, Taiwan.
authors.forename: C H
authors.initials: CH
authors.lastname: Chen
authors.forename: H C
authors.initials: HC
authors.lastname: Wang
authors.forename: N N
authors.initials: NN
authors.lastname: Chuang
mesh_terms: D016475:3T3 Cells; D000818:Animals; D015153:Blotting, Western; D000081247:CSK Tyrosine-Protein Kinase; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism*; D003001:Cloning, Molecular; D033364:Decapoda / Q000235:genetics / Q000378:metabolism*; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*; D019061:src-Family Kinases
chemical_list: C495541:Cav1 protein, mouse; C495537:Cav1 protein, rat; D051242:Caveolin 1; D022461:Caveolins; D004791:Enzyme Inhibitors; D011993:Recombinant Fusion Proteins; D006160:Guanosine Triphosphate; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; D020558:GTP Phosphohydrolases; D018631:ras Proteins