Induction of phosphatidylcholine synthesis in cho cells by sPLA2

Phosphatidylcholine (PC) is the major phospholipid in mammalian cell mem branes and is tightly regulated to maintain homeostasis. Treatments that cause PC degradation stimulate PC synthesis and vice versa. Previous work in Chi nese hamster ovary ( CHO ) relis shows that degradation of PC by phospholipase C (PI.C) induces new synthesis of PC. Other work in rat hepatocytes shows that exogenous secretory phospholipase A2 (sPLAj) also stimulates PC synthesis. Our present work seeks to determine if the sPLAa induced anabolism of PC involves the modulation of CTP:phosphocholine cytidylyltransferase (CT) activity. sPL.\2 (from aja mossambica mossambica) added to CHO cells induces the catabolism of PC as shown by increased [3H]-lysoPC production. sPLAj also increases PC synthesis as shown by increased incorporation of [3H]choline into PC. Interestingly, whole eel! homogenates of sPLA2 treated CHO rdls show no associated increase in CT activity. However, CT activity increases when CHO cells are treated with PLC. Together, these data suggest that the mechanism of inducing PC synthesis may vary depending on the mechanism by which PC is degraded. Studies are continuing to identify the factors influence the induction of PC synthesis by sPLA->. Supported by NSF grant MCB95071U.

Duke Scholars

Author Suzanne Barbour Cell Biology