Phosphatidic acid metabolization in nuclei from cerebral cortex and cerebellum

CAMPELO, ADRIÁN E.; PASQUARÉ, SUSANA E.; GIUSTO, NORMA M

Rosario, Santa Fe, Argentina

Congreso; 42º Reunión anual de la "Sociedad Argentina de Investigación en Bioquímica y Biología Molecular" (SAIB); 2006

SAIB

LI-P21 PHOSPHATIDIC ACID METABOLIZATION IN NUCLEI FROM CEREBRAL CORTEX AND CEREBELLUM Campelo, A.E., ; Pasquaré, S.J.; Giusto, N.M. Instituto de Investigaciones Bioquímicas de Bahía Blanca, B8000FWB Bahía Blanca, Argentina E-mail: pasquare@criba.edu.ar We have reported that in the Central Nervous System phosphatidic acid is metabolized to diacylglycerol (DAG) by the isoforms of phosphatidate phosphohydrolase (namely, PAP1 and PAP 2) and that DAGs generated by PAPs are partially metabolized to monoacylglycerols (MAG) by diacylglyceride lipase (DGL) activity. The aim of the present work was to study which PAP isoforms are associated to nuclei in the cerebellum and cerebral cortex (CC). To this end, adult (4 mo) rat CC and cerebellums were homogenized and highly purified nuclei were isolated by sucrose-density ultracentrifugation. Nuclear preparations were checked for purity by electron microscopy. The different PAP isoforms were assayed according to their NEM sensitivity (Methods in Enzymol., 197, 553-563, 1991). The DGLs activities were assayed using DAG as substrate, which was generated by PAPs action. Our results indicate that NEMsensitive (PAP-1) is predominantly present in nuclei from CC while NEM-insensitive (PAP-2) evidences a similar activity in nuclei from both CC and cerebellum. In addition, it was observed that nuclear DGL activity is higher in the cerebellum than in CC. The PA metabolization in nuclei is indicative of an important signalling pathway in this fraction.