Artículo
Functional human sperm capacitation requires both bicarbonate dependent-PKA activation and down-regulation of Ser/Thr phosphatases by Src family kinases
Battistone, Maria Agustina
; Da Ros, Vanina Gabriela
; Salicioni, A.; Navarrete, F.; Krapf, Dario
; Visconti, P. E.; Cuasnicu, Patricia Sara
Fecha de publicación:
29/04/2013
Editorial:
Oxford University Press
Revista:
Molecular Human Reproduction.
ISSN:
1360-9947
e-ISSN:
1460-2407
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
In all mammalian species studied so far, sperm capacitation correlates with an increase in protein tyrosine (Tyr) phosphorylation mediated by a bicarbonate-dependent cAMP/PKA pathway. Recent studies in mice revealed however that a Src Family Kinase (SFK) induced inactivation of serine/threonine (Ser/Thr) phosphatases is also involved in the signaling pathways leading to Tyr phosphorylation. In view of these observations and with the aim of getting a better understanding of the signaling pathways involved in human sperm capacitation, in the present work we investigated the involvement of both the cAMP/PKA and SFK/phosphatase pathways in relation to the capacitation state of the cells. For this purpose, different signaling events and sperm functional parameters were analyzed as a function of capacitation time. Results revealed a very early bicarbonate-dependent activation of PKA indicated by the rapid (1 min) increase in both phospho-PKA substrates and cAMP levels (p<0.05). However, a complete pattern of Tyr phosphorylation was detected only after 6 h-incubation at which time sperm exhibited the ability to undergo the acrosome reaction (AR) and to penetrate zona-free hamster eggs. Sperm capacitated in the presence of the SFK inhibitor SKI606 showed a decrease in both PKA substrate and Tyr phosphorylation levels which was overcome by exposure of sperm to the Ser/Thr phosphatase inhibitor okadaic acid (OA). However, OA was unable to induce phosphorylation when sperm were incubated under PKA-inhibitory conditions (i.e. in the absence of bicarbonate or presence of PKA inhibitor). Moreover, the increase in PKA activity by exposure to a cAMP analogue and a phosphodiesterase inhibitor did not overcome the inhibition produced by SKI606. Whereas the presence of SKI606 during capacitation produced a negative effect (p<0.05) on sperm motility, progesterone-induced AR and fertilizing ability, none of these inhibitions were observed when sperm were exposed to SKI606 and OA. Interestingly, different concentrations of inhibitors were required to modulate human and mouse capacitation revealing the species-specificity of the molecular mechanisms underlying this process. In conclusion, our results describe for the first time the involvement of both PKA activation and Ser/Thr phosphatase down-regulation in functional human sperm capacitation and provide convincing evidence that early PKA-dependent phosphorylation is the convergent regulatory point between these two signaling pathways.
Palabras clave:
Capacitation
,
Human Sperm
,
Pka
,
Phosphatase
Archivos asociados
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Identificadores
Colecciones
Articulos(CCT - ROSARIO)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - ROSARIO
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - ROSARIO
Articulos(IBR)
Articulos de INST.DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Articulos de INST.DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Articulos(IBYME)
Articulos de INST.DE BIOLOGIA Y MEDICINA EXPERIMENTAL (I)
Articulos de INST.DE BIOLOGIA Y MEDICINA EXPERIMENTAL (I)
Citación
Battistone, Maria Agustina; Da Ros, Vanina Gabriela; Salicioni, A.; Navarrete, F.; Krapf, Dario; et al.; Functional human sperm capacitation requires both bicarbonate dependent-PKA activation and down-regulation of Ser/Thr phosphatases by Src family kinases; Oxford University Press; Molecular Human Reproduction.; 19; 9; 29-4-2013; 570-580
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