Capacitation induces tyrosine phosphorylation of proteins in the boar sperm plasma membrane

Capacitation (activation) of mammalian spermatozoa is accompanied by protei n phosphorylation, elevation of the intracellular calcium concentration and an increased plasma membrane fluidity. The subcellular localization of tyr osine phosphorylation during capacitation have not yet been elucidated. The aim of this study was to investigate whether boar sperm capacitation induc es tyrosine phosphorylation of plasma membrane proteins. Capacitation induc ed tyrosine phosphorylation of 3 proteins (27, 37, and 40 kDa), which coinc ided with an increase in the plasma membrane fluidity, The importance of th e induced tyrosine phosphorylation in sperm binding to the zona pellucida a nd the induction of the acrosome reaction is discussed. (C) 1999 Academic P ress.