Membrane restructuring induced by the enzymatic generation of ceramides with very long chain PUFA.

PEÑALVA, D.A.; ANTOLLINI, S.S.; AMBROGGIO, E.E.; AVELDAÑO, M.I.; FANANI, M.L.

Cordoba

Congreso; 52 Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2016

Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular

Sphingolipids in most mammalian tissues typically contain saturated and monounsaturated acyl chains from C14 to C24. Notable exceptions are spermatozoa of various mammals, including man, which contain SM and Cer species with infrequent series of very long chain (C24 to C36) polyunsaturated fatty acids (VLCPUFA). In rat sperm, these SM species are exclusively located on the heads. After acrosomal reaction almost complete hydrolysis of such SMs occurs, leading to gametes enriched in the corresponding Cer species. In the present study we evaluated the integrity and structure of the bilayer during the enzymatic formation of Cer in binary POPC/SM vesicles. SM containing VLCPUFA were isolated from rat testes by a combination of chromatographic techniques. Egg-SM was used for comparison. We evaluated different biophysical parameters during SM → Cer enzymatic hydrolysis in LUVs: 1) liposomes size; 2) augmentation in the interaction between different populations; and 3) in-plane lateral organization after Cer generation; also we studied the structural membrane reorganization using GUVs and confocal microscopy. Our results show an enhanced membrane restructuring capacity for the resultant V-Cer. The longer and bulkier acyl chains of V-Cer may play a role in favouring the fusion/fission events that occur in the head of spermatozoa during the acrosomal reaction