Molecular and Cellular Aspects of Mammalian Sperm Acrosomal Exocytosis

STIVAL C; KRAPF D; BUFFONE MG; LA SPINA FA

Animal Models and Human Reproduction

John Wiley & Sons, Inc

Año: 2017; p. 409 - 426

During capacitation, sperm activate a complex cascade of signaling pathways leading to acquire two essential features: the development of hyperactivated motility and the ability to undergo acrosomal exocytosis upon stimulation with the proper stimuli. Mammalian sperm must undergo acrosomal exocytosis to penetrate the extracellular matrix surrounding the egg, named zona pellucida (ZP). Acrosomal exocytosis shares many molecular mechanisms in common with other cellular secretory processes. However, there are some features that make this process a special type of regulated secretion: a single exocytotic granule per cell is involved; there is no membrane recycling; and rather than a single vesicle-plasma membrane union point, fusion between the outer acrosomal and the plasma membranes occurs at multiple sites to destabilize the structure of the acrosome. Protein kinase A (PKA) plays a pivotal role in almost all known aspects of sperm capacitation, not only restricted to fast events. In mouse sperm, PKA coimmunoprecipitates with the tyrosine kinase Src.