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Participation of protein kinases and phosphatases in the progesterone‐induced acrosome reaction and calcium influx in human spermatozoa
Author(s) -
Barón L.,
Fara K.,
ZapataCarmona H.,
Zuñiga L.,
Kong M.,
Signorelli J.,
Díaz E. S.,
Morales P.
Publication year - 2016
Publication title -
andrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.947
H-Index - 43
eISSN - 2047-2927
pISSN - 2047-2919
DOI - 10.1111/andr.12234
Subject(s) - acrosome reaction , phosphatase , calcium , kinase , protein kinase c , second messenger system , calcium in biology , chemistry , biochemistry , microbiology and biotechnology , medicine , biology , endocrinology , intracellular , enzyme , in vitro
Summary In human spermatozoa, protein kinases have a role in the acrosome reaction (AR) induced by a variety of stimuli. However, there is disagreement or a lack of information regarding the role of protein kinases and phosphatases in the progesterone (P)‐induced increase in intracellular calcium concentration ([Ca 2+ ] i ). In addition, there are no studies regarding the role of Ser/Thr and Tyr phosphatases and there are contradictory results regarding the role of Tyr kinases in the P‐induced acrosome reaction. Here, we performed a simultaneous evaluation of the involvement of protein kinases and phosphatases in the P‐induced acrosome reaction and in the P‐induced calcium influx. Motile spermatozoa were capacitated for 18 h and different aliquots were allocated to treated or control groups and then evaluated for their ability to undergo the acrosome reaction and to increase [Ca 2+ ] i in response to P. The acrosome reaction was evaluated using Pisum sativum agglutinin (PSA)‐FITC, and [Ca 2+ ] i was evaluated using fura 2AM. At all of the concentrations tested, PKA inhibitors significantly reduced the percentage of the P‐induced acrosome reaction ( p < 0.001). However, only the highest concentrations of PKA inhibitors reduced the P‐induced calcium influx; lower concentrations of PKA inhibitors did not affect it. Similar results were apparent for PKC inhibitors and for tyrosine kinase inhibitors. None of the Ser/Thr phosphatase inhibitors affected the P‐induced acrosome reaction or the P‐induced calcium influx, except for the PP2B inhibitors that significantly reduced the P‐induced acrosome reaction without affecting calcium influx. Finally, the protein tyrosine phosphatase inhibitors significantly blocked the P‐induced acrosome reaction and reduced the amplitude of the P‐induced calcium transient ( p < 0.001) as well as the amplitude of the plateau phase ( p < 0.01). The data suggest that protein kinases and possibly PP2B have a role on the acrosome reaction at some point downstream of calcium entry and that Tyr phosphatases have a role on the acrosome reaction upstream of calcium entry.