Biochem Biophys Res Commun 2003 Jan 31;3011:13-6. doi: 10.1016/s0006-291x(02)02979-0.

Mastoparan induces Ca2+-independent cortical granule exocytosis in sea urchin eggs.

???displayArticle.abstract???
In most species, cortical granule exocytosis is characteristic of egg activation by sperm. It is a Ca(2+)-mediated event which results in elevation of the vitelline coat to block permanently the polyspermy at fertilization. We examined the effect of mastoparan, an activator of G-proteins, on the sea urchin egg activation. Mastoparan was able to induce, in a concentration-dependent manner, the egg cortical granule exocytosis; mastoparan-17, an inactive analogue of mastoparan, had no effect. Mastoparan, but not sperm, induced cortical granule exocytosis in eggs preloaded with BAPTA, a Ca(2+) chelator. In isolated egg cortical lawns, which are vitelline layers and membrane fragments with endogenously docked cortical granules, mastoparan induced cortical granule fusion in a Ca(2+)-independent manner. By contrast, mastoparan-17 did not trigger fusion. We conclude that in sea urchin eggs mastoparan stimulates exocytosis at a Ca(2+)-independent late site of the signaling pathway that culminates in cortical granule discharge.

???displayArticle.pubmedLink??? 12535633
???displayArticle.link??? Biochem Biophys Res Commun


Genes referenced: LOC100887844