Mechanism of Phosphatidylserine-Induced Inhibition of Interleukin 2 Synthesis in the Human T Cell Line Jurkat

Abstract

Phosphatidylserine has been implicated both in the regulation of protein kinase C activity and in the regulation of T lymphocyte activation in vitro and in vivo. Treatment of Jurkat T cells with PS, results in a strong decrease of Interleukin-2 synthesis. Arachidonoyl-diacylglycerol production and Ca⁺⁺ mobilization due to the increase of the phosphatidylinositide turnover appeared not affected by PS. On the contrary, oleoyl-diacylglycerol production arising from phosphatidylcholine breakdown was impaired. Studies on phospholipid synthesis in PS-treated cells suggest 1) that the phospholipid methylation pathway that lead to the conversion of phosphatidylethanolamine into phosphatidylcholine is the major site of action of exogenous added PS and 2) confirm that this pathway is a major source of oleoyl-diacylglycerol in Jurkat T cells.