MOLECULAR MECHANISMS INVOLVED IN PROTEIN TYROSINE PHOSPHORYLATION INHIBITION DURING CRISP1 KNOCKOUT SPERM CAPACITATION

MALDERA JA; BATTISTONE MA; PAGOTTO R; PIGNATARO OP; COHEN DJ ; CUASNICU PS

Buenos Aires

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

Sociedad Argentina de Biología (SAB)

CRISP1 protein associates with sperm during epididymal maturationand participates in fertilization. Interestingly, sperm fromCrisp1-/- mice generated in our laboratory exhibit lower levels ofcapacitation-associated protein tyrosine phosphorylation. In thepresent work, we further investigated the mechanisms underlyingthis inhibition in CRISP1-deficient sperm. Capacitation of Crisp1-/- sperm in the presence of purified native CRISP1 did not restoretyrosine phosphorylation levels. Considering that tyrosine phosphorylationis regulated by a cAMP-dependent pathway, we evaluatedthe occurrence of this event in Crisp1-/- sperm exposed to botha cAMP analog and a phosphodiesterase inhibitor. Results showedthat, under these conditions, there was a reversion in Crisp1-/- spermphosphorylation levels supporting the existence of a lower contentof cAMP in mutant sperm. This possibility was confirmed by thesignificantly lower levels of cAMP determined by RIA. Consideringthat sperm acquire both CRISP1 and the ability to undergo capacitationduring their transit through the epididymis, our resultssuggest that the inhibition in tyrosine phosphorylation in Crisp1-/-sperm might be due to the lack of CRISP1 association during epididymalmaturation