Protein tyrosine phosphorylation in sperm during gamete interaction in themouse: The influence of glucose

A key intracellular event during capacitation is protein tyrosine phosphory lation, but its involvement during sperm interaction with the oocyte has no t been investigated. Glucose is necessary to achieve fertilization and thus may have an influence on sperm protein tyrosine phosphorylation. The objec tives of this study were to 1) visualize protein tyrosine phosphorylation p atterns in sperm during capacitation and interaction with the oocyte and 2) determine the influence of glucose. Protein tyrosine phosphorylation was i nvestigated by Western analysis and immunofluorescence. Protein tyrosine ph osphorylation was increased during capacitation, and immunofluorescence rev ealed that zona binding and gamete fusion were correlated with an increase in tyrosine phosphorylation of proteins in the midpiece. During capacitatio n, the absence of glucose led to a delay in the appearance of protein tyros ine phosphorylation. Following binding to the zona pellucida and the oolemm a, tyrosine phosphorylation in the flagellum was also delayed in the absenc e of glucose and resulted in a significant inhibition of the midpiece phosp horylation. The correlation between successful gamete fusion and the tyrosi ne phosphorylation of midpiece proteins suggests that the effect of glucose on sperm-oocyte interaction is mediated through regulation of protein tyro sine phosphorylation in a specific area of the fertilizing sperm.