Differential regulation of phosphatidylcholine-derived signaling pathways in synaptic membrane rafts.

MATEOS MELINA; SALVADOR GABRIELA; GIUSTO NORMA

San Miguel de Tucuman

Congreso; XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB),; 2009

XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB),

Age-associated changes in the lipid composition  of synaptic membrane rafts Mateos, M.V.; Salvador, G.A and Giusto, N.M. Instituto de Investigaciones Bioquímicas de Blanca. UNS-CONICET Specialized membrane microdomains known as ‘membrane rafts’(MR) contain protein complexes involved in many signal transduction processes. This study was undertaken to determine the lipid composition of cerebral cortex synaptic membrane rafts (SMR) obtained from adult (4 month –old)  and aged (28 month-old) rats. SMR  showed an enrichment in cholesterol and sphingomielyn (SM) content with respect to isolated synaptic endings. Additionally, SM content increased by 20 % in SMR obtained from aged animals with respect to adults SMR. Comparison of the distribution of  the individual phospholipid and  acyl  chain composition of both SMR  preparations with respect to isolated synaptic endings  showed  an enrichment in phosphatidylcholine (PC), and a decrease in phosphatidylethanolamine (PE) and phosphatidylserine (PS) content by 40 %, 20 % and 10% respectively. Total phospholipid-fatty acid composition from MR presented an enrichment in 18:0 (40%), and a decrease 20:4 (10%) and 22:6 (50%) content in adult animals.  Fatty acid composition of PC, PE and PS showed the same profile than that observed in total phospholipids observed in MR from adult rats. A similar profile of fatty acid composition was observed in SMR obtained from aged animals. However the 20:4 and 22:6 content  significantly decreased (50 % and 80 % , respectively) with respect to SMR from adults. Our results show that lipid composition of MR is affected during aging and that age promotes a more saturated……..