blocked the elevation of the vitelline layer by uncaged InsP 3 , despite the massive release of
Ca
2+
, implying that exocytosis of the cortical granules requires not only a Ca
2+
rise, but also regulation of the
cortical actin cytoskeleton. Our results suggest that the cortical actin cytoskeleton of starfish oocytes plays
critical roles both in generating Ca
2+
signals and in regulating cortical granule exocytosis.