... at fertilization. This Ca 2+ rise is crucial for all subsequent egg activation steps, such as cortical granule exocytosis, which modifies the vitelline membrane to prevent polyspermy. The cytosolic Ca 2+ rise is primarily initiated by inositol 1,4,5-trisphosphate(IP 3 )-mediated Ca 2+ release from the endoplasmic...

... exhibited similar inhibition of degranulation, it had minimal effects on chromosome segregation. These observations lead us to speculate that SEP-1 has two separable yet coordinated functions: to regulate cortical granule exocytosis and to mediate chromosome separation. Our data indicate that exocytosis...