Coexistence of phosphatidylcholine-specific phospholipase C and phospholipase D activities in rat cerebral cortex synaptosomes

MATEOS M.V.; URANGA R.M.; SALVADOR G.A.; GIUSTO N.M.

LIPIDS

SPRINGER HEIDELBERG

Año: 2006 vol. 41 p. 1 - 8

0024-4201

  ABSTRACT: DAG derived from phosphatidylcholine (PtdCho) acts as a lipid second messenger. It can be generated by the activation of phospholipase D (PLD) and the phosphatidic acid phosphohydrolase type 2 (PAP2) pathway or by a PtdCho-specific phospholipase C (PtdCho-PLC). Our purpose was to study PtdCho-PLC activity in rat cerebral cortex synaptosomes (CC Syn). DAG production was highly stimulated by detergents such as Triton X-100 and sodium deoxycholate. Ethanol and tricyclodecan-9-yl-xanthate potassium salt decreased DAG generation by 42 and 61%, respectively, at 20 min of incubation. These data demonstrate that both the PLD/PAP2 pathway and PtdCho-PLC contribute to DAG generation in CC Syn. PtdCho-PLC activity remained located mainly in the synaptosomal plasma membrane fraction. Kinetic studies showed Km and Vmax values of 350 ìM and 3.7 nmol DAG x (mg protein xh)-1, respectively. Western blot analysis with anti-PtdCho-PLC antibody showed a band of 66 KDa in CC Syn. Our results indicate the presence of a novel DAG-generating pathway in CC Syn in addition to the known PLD/PAP2 pathway.