Reactivation of motility of demembranated hamster spermatozoa: role of protein tyrosine kinase and protein phosphatases

Demembranated cauda epididymidal spermatozoa of hamster, following reactivation with I mm ATP, exhibited either a loop or planar type of motility. The spermatozoa with planar motility exhibited increased progressive velocity (VSL), straightness (STR) linearity (LIN) and beat cross frequency (BCF) compared to the spermatozoa with loop type motility. cAMP was observed to have differential effects on the motility parameters of the demembranated spermatozoa depending on the type of motility. For instance, in the loop type, average path velocity (YAP), curvilinear velocity (VCL) and VSL were increased in the presence of cAMP Unlike in the planar type. Furthermore, in an attempt to understand the role of protein kinases and protein phosphatases in regulation of sperm motility, the effects of various inhibitors of these enzymes on the motility and phosphorylation of proteins of reactivated demembranated spermatozoa were studied. Inhibitors of PTKase (protein tyrosine kinase) and protein phosphatases inhibited the motility of reactivated demembranated hamster spermatozoa. The activity of the respective enzymes associated with demembranated spermatozoa was concurrently inhibited, thus providing evidence that the effect of the inhibitors on motility was mediated through their inhibitory effects on the activities of the enzymes. The results also demonstrated that two phosphotyrosinylated proteins of molecular weight 65 and 80 kDa showed reduced phosphorylation in the presence of PTKase inhibitors, thus indicating their possible role in reactivation of motility of demembranated hamster spermatozoa.