SNAP IS INVOLVED IN CORTICAL GRANULES EXOCYTOSIS AND POLARITY IN MOUSE OOCYTES

DE PAOLA, M. MATILDE; RINALDINI, E; CAPPA, ANDREA I.; MAYORGA, LUIS S.; BATIZ, LUIS F.; MICHAUT, MARCELA A.

Llanuras de Diana, Puerto Natales

Workshop; European Molecular Biology Organization (EMBO) Workshop: Current advances in membrane trafficking: Implications for polarity and diseases; 2014

European Molecular Biology Organization (EMBO)

SNAPs play a key role in different aspects of cell biology such as membrane fusion events, including vesicular traffic and exocytosis, and many others like cell polarity, cell division and apoptosis. SNAPs act as an adaptor protein that physically links SNAREs to NSF, thereby mediating disassembly and recycling of SNARE complexes. It has been shown that SNAP/NSF complex is essential for ER to Golgi transport, homotypic endosome  fusion, TGN to basolateral and apical membranes transport, proteins transport in polarized cells, synaptic vesicle fusion in neurons and many other exocytosis such as lung surfactant, secretory granule fusion in chromaffin cells, insulin secretion in islets of Langerhans and sperm acrosome reaction. In female mammals, cortical granules (CG) exocytosis is the primary mechanism in preventing polyspermic fertilization. We demonstrated for the first time the presence of SNAP/NSF complex in mammalian oocytes, using RT-PCR, WB and IFI techniques in mice model. Furthermore, this complex is necessary for CG exocytosis since microinjection of specific antibodies inhibit this process. Hydrocephalus with hop gait (hyh) is a recessive inheritable mouse disease that arose spontaneously in C57BL/10J mouse strain. A missense mutation in the gene encoding for alpha-SNAP causes the substitution of a highly conserved methionine at amino acid residue 105 for isoleucine (M105I). Due to alpha-SNAP knockout mice is embryonically lethal in mice, the hyh mice provide a unique in vivo model to investigate á-SNAP function. We have determined that hyh female have a strongly reduced in vivo and in vitro fertility, with higher polyspermic rates. Aditionally, some hyh oocytes show an abnormal CG distribution suggesting that alpha-SNAP might have a function in CG migration. Altogether, our results suggest that alpha-SNAP/NSF complex is involved not only in membrane fusion events such as exocytosis but also in CG migration and/or cell polarity.