Harvey M. Florman*, Melissa K. Jungnickel and Keith A. Sutton
Department of Cell Biology, University of Massachusetts Medical School, Worcester, MA, USA
The acrosome reaction is a secretory event that must be completed by the sperm of many animal species prior to fusion with eggs. In mammals, exocytosis in triggered by ZP3, a glycoprotein component of the egg pellucida, following gamete contact. ZP3 promotes a sustained influx of Ca2+ into sperm that is necessary for the acrosome reaction. Here, we discuss the mechanism by which ZP3 generates Ca2+ entry, as well as the upstream events leading to this influx and downstream processes that couple it with exocytosis.
acrosome reaction, signal transduction calcium channel, TRPC channel, PI3, kinase