The microinjection of MARCKS effector domain inhibits cortical granules exocytosis in mouse eggs

GALLO, GIOVANNA L.; BELLO, OSCAR D.; DE PAOLA, M. MATILDE ; MAYORGA, LUIS S.; MICHAUT, MARCELA A.

Buenos Aires

Congreso; Sociedad Argentina de Biología; 2010

Cortical granule exocytosis is a crucial secretory process that blocks polyspermy and enables successful embryonic development. Nevertheless, the molecular mechanism of this particular exocytosis remains unknown. We have reported that MARCKS, a prominent substrate of PKC involved in exocytosis in different cell types, is expressed in mouse eggs. We hypothesized that MARCKS is involved in cortical granule exocytosis in mouse eggs. To test this hypothesis, we analyze the effect of MARCKS effector domain in a functional assay of cortical granule exocytosis. We purified MARCKS effector domain as a GST-fusion protein and microinjected mouse eggs before activate them parthenogenetically with SrCl2. As a control, we microinjected GST protein. Results showed that only the microinjection of MARCKS effector domain was able to inhibit cortical granule exocytosis stimulated by SrCl2 when compared to control. In addition, the extent of this inhibition was dependent on the concentration of MARCKS effector domain. These data validate our hypothesis and suggest that MARCKS is involved in the signal transduction pathways that lead to cortical granule exocytosis in mouse eggs.