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

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

LIPIDS

AOCS Press

Lugar: USA; Año: 2006 vol. 41 p. 273 - 280

0024-4201

Diacylglycerol (DAG) derived from phosphatidylcholine (PtdCho) acts as a lipid second messenger and it can be generated by the activation of phospholipase D (PLD) and phosphatidic acid phosphohydrolase type 2 (PAP2) pathway or by a phosphatidylcholine-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 D609 decreased DAG generation by 42% and 61%, respectively at 20 min incubation. These data demonstrate that both 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 mM and 3.7 nmol DAG x (mg protein x hour)-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 synaptosomes, besides the known PLD/PAP2 pathway.