Co-existence of Phosphatidylcholine-Specific Phospholipase C and Phospholipase D Activities in Rat Cerebral Cortex Synaptosomes

MATEOS MELINA,; URANGA ROMINA,; SALVADOR, GABRIELA ALEJANDRA; GIUSTO NORMA,

LIPIDS

AOCS press

Lugar: USA; Año: 2006 p. 273 - 280

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 µM and 3.7 nmol DAG × (mg protein × h)−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. Paper no. L9873 in Lipids 41, xxx–xxx (March 2006).