PARTICIPATION OF TIROSINE KINASE SRC FAMILY IN RAT SPERM CAPACITATION

BATTISTONE MA,; MALDERA JA; WEIGEL MUÑOZ M; KRAPF D; VISCONTI P; CUASNICU PS

Buenos Aires

Jornada; XII Jornadas Multidisciplinarias de la Sociedad Argentina de Biología (SAB); 2010

Sociedad Argentina de Biología (SAB)

Sperm capacitation relies on an increase in protein tyrosine phosphorylation mediated by PKA activation. Recent studies have suggested that Src tyrosine kinase family (SKF) is involved either direct or indirectly in capacitation-associated protein tyrosine phosphorylation. In order to elucidate between these two possibilities, we investigated whether SFK is involved in the signaling events leading to rat sperm capacitation. Results showed that sperm capacitated in the presence of a SFK inhibitor (SU6656), exhibited low levels of both tyrosine and PKA- substrates phosphorylation. Based on the described inhibition of ser/thr phosphatases by SFK, sperm were exposed to a Ser/Thr phosphatases inhibitor (okadaic acid, OA) observing a reversion of the impaired-phosphorylation produced by SU6656. However, OA was unable to induce tyrosinephosphorylation in both uncapacitated sperm and sperm capacitated in the presence of a PKA inhibitor. Finally, addition of both a cAMP agonist and a phosphodiesterase inhibitor did not overcome the inhibition produced by SU6656. Altogether, these results show the indirect involvement of SFK in rat sperm tyrosine phosphorylation supporting the existence of two parallel pathways leading to capacitation: one requiring PKA activation, and the other involvingthe inactivation of ser/thr phosphatases.