Sphingosine induces p125FAK and paxillin tyrosine phosphorylation, actin stress fiber formation, and focal contact assembly in Swiss 3T3 cells.

摘要: Treatment of Swiss 3T3 cells with sphingosine, a potential breakdown product all sphingolipids, induced tyrosine phosphorylation multiple substrates including bands M(r) 110,000-130,000 and 70,000-80,000. Tyrosine in response to sphingosine occurred concentration dependent manner (EC50 = 10 microM) developed gradually reaching half maximum effects at 20 60 min, respectively. The dihydroenantiomere DL-threo-dihydrosphingosine, neither nor interfered sphingosine-stimulated phosphorylation. Focal adhesion kinase (p125FAK) paxillin were identified as prominent for Cell permeable ceramides also stimulated the band well p125FAK, but effect was less pronounced than that sphingosine. by could be dissociated from both protein C activation Ca2+ mobilization intracellular stores. Sphingosine striking actin stress fiber formation focal assembly cells. kinetics closely paralleled. Cytochalasin D, which disrupts network microfilaments, completely inhibited In addition, p125FAK prevented when presence platelet-derived growth factor (30 ng/ml) caused disruption cytoskeleton. Our results demonstrate, first time, induces phosphorylation,