Therefore, we used PD098059 as a pharmacological tool to study the involvement of ERKs in the induction of the capacitation state in human spermatozoa. To this end, spermatozoa were selected by swim-up procedure for 2 h at 37°C in complete, capacitating medium or in the presence of PD098059 (10 and 100 |xM). No differences were […]
Effect of Inhibition of ERK Activation on Human Sperm Capacitation PD098059 is a recently developed compound, able to inhibit MEK activity and therefore phosphorylation and activation of ERKs. Figure 10 shows Western blot analysis using an antibody directed against MEK-1 of human sperm lysates. A band migrating at the expected 45-kDa molecular mass was observed […]
Figure 8A shows a capacitation-dependent increase in the tyrosine-phosphorylated form of ERK-2. No other protein bands were detected (not shown). When the same blot, after stripping, was reprobed with allcp42 antibody, a single band comigrating with the tyrosine-phosphorylated form of ERK-2, with equal intensity in each lane, was observed (Fig. 8B).
These data were confirmed by immunoprecipitation experiments in which sperm proteins obtained at 1- and 24-h capacitation were immunoprecipitated with cdlcp42 antibody and then blotted with PY20 antibody (Fig. 7A), stripped, and reprobed with alcp44 antibody (Fig. 7B). In these conditions, two tyrosine-phosphorylated bands of 42- and 44-kDa molecular mass corresponding to ERK-2 and ERK-1 […]
The occurrence of ERKs in sperm cells appears to be an early event during spermatogenesis. We have demonstrated the presence of ERKs in testicular germ cells at any stage of sperm development. In these cells, ERKs were predominantly localized to the nuclei, where they might regulate gene transcription, maturation, and differentiation. In this connection, the […]
In addition, several integrin chains present in mammalian spermatozoa have been shown to play a role in binding of spermatozoa to the oocyte, and the expression of these molecules is regulated during capacitation. The involvement of ERKs in regulation of the integrin affinity state has been reported. In this scenario, sperm ERKs may regulate activity […]
The present paper shows the presence of ERKs in human spermatozoa and establishes a biological role for these enzymes in sperm capacitation. Indeed, we demonstrate here that in vitro capacitation stimulates a sustained and concomitant increase in tyrosine phosphorylation and kinase activity of ERKs, indicating activation of these enzymes during capacitation. Furthermore, our results suggest […]