Sphingosine, sphingosylphosphorylcholine and sphingosine 1-phosphate modulate phosphatidylserine homeostasis in glioma C6 cells

The effect of sphingosine, sphingosylphosphorylcholine and sphingosine 1-ph osphate on L-[U-C-14]serine incorporation into phosphatidylserine and phosp hatidylserine-derived phosphatidylethanolamine was investigated in intact g lioma C6 cells. Sphingosine, sphingosylphosphorylcholine and sphingosine 1- phosphate are potent signalling molecules which, due to their physicochemic al features, may function as amphiphilic compounds. It has been found that sphingosine and sphingosylphosphorylcholine (amphiphilic cations) significa ntly increase [C-14]phosphatidylserine synthesis and decrease the amount of C-14-labeled phosphatidylethanolamine. Sphingosine 1-phosphate (an amphiph ilic anion) was without effect on phosphatidylserine synthesis but, similar ly as sphingosine and sphingosylphosphorylcholine, reduced the conversion o f phosphatidylserine to phosphatidylethanolamine. These results strongly su ggest that sphingosine, sphingosylphosphorylcholine and sphingosine 1-phosp hate can modulate cellular phospholipid homeostasis by stimulation of phosp hatidylserine synthesis and an interference with phosphatidylserine decarbo xylase.