Activation of phospholipase C-Ca2+ system by sphingosine 1-phosphate in CHO cells transfected with Edg-3, a putative lipid receptor

Sphingosine l-phosphate (S1P) induces phospholipase C (PLC) activation and Ca2+ mobilization in many types of cells. We examined the possible involvem ent of Edg-3, one of the putative S1P receptors, in the phospholipase C (PL C)-Ca2+ system. S1P increased the cytoplasmic free Ca2+ concentration,witho ut detectable inositol phosphate production in vector-transfected CHO cells . In the Edg-3-transfected cells, however, the S1P-induced Ca2+ response,va s clearly enhanced, which was associated with a significant production of i nositol phosphate. These SIP-induced responses in the Edg-3-transfected cel ls were inhibited by U73122, a potent PLC inhibitor. We conclude that Edg-3 may be one of the S1P receptors participating in the activation of the PLC -Ca2+ system. (C) 1999 Federation of European Biochemical Societies.