title: Participation of protein kinases and phosphatases in the progesterone-induced acrosome reaction and calcium influx in human spermatozoa.
abstract: 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 ([Ca2+]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 [Ca2+]iin response to P. The acrosome reaction was evaluated using Pisum sativum agglutinin (PSA)-FITC, and [Ca2+]iwas 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.
authors.affiliation: Laboratory of Biology of Reproduction, Department of Biomedicine, Faculty of Health Sciences, University of Antofagasta, Antofagasta, Chile.
authors.forename: L
authors.initials: L
authors.lastname: Barón
authors.affiliation: Laboratory of Biology of Reproduction, Department of Biomedicine, Faculty of Health Sciences, University of Antofagasta, Antofagasta, Chile.
authors.forename: K
authors.initials: K
authors.lastname: Fara
authors.affiliation: Laboratory of Biology of Reproduction, Department of Biomedicine, Faculty of Health Sciences, University of Antofagasta, Antofagasta, Chile.
authors.forename: H
authors.initials: H
authors.lastname: Zapata-Carmona
authors.affiliation: Laboratory of Biology of Reproduction, Department of Biomedicine, Faculty of Health Sciences, University of Antofagasta, Antofagasta, Chile.|Antofagasta Institute, University of Antofagasta, Antofagasta, Chile.
authors.forename: L
authors.initials: L
authors.lastname: Zuñiga
authors.affiliation: Laboratory of Biology of Reproduction, Department of Biomedicine, Faculty of Health Sciences, University of Antofagasta, Antofagasta, Chile.
authors.forename: M
authors.initials: M
authors.lastname: Kong
authors.affiliation: Laboratory of Biology of Reproduction, Department of Biomedicine, Faculty of Health Sciences, University of Antofagasta, Antofagasta, Chile.
authors.forename: J
authors.initials: J
authors.lastname: Signorelli
authors.affiliation: Laboratory of Biology of Reproduction, Department of Biomedicine, Faculty of Health Sciences, University of Antofagasta, Antofagasta, Chile.
authors.forename: E S
authors.initials: ES
authors.lastname: Díaz
authors.affiliation: Laboratory of Biology of Reproduction, Department of Biomedicine, Faculty of Health Sciences, University of Antofagasta, Antofagasta, Chile.|Antofagasta Institute, University of Antofagasta, Antofagasta, Chile.
authors.forename: P
authors.initials: P
authors.lastname: Morales
mesh_terms: D020101:Acrosome Reaction / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D006801:Humans; D008297:Male; D011374:Progesterone / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013075:Sperm Capacitation / Q000187:drug effects / Q000502:physiology; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism*
chemical_list: D047428:Protein Kinase Inhibitors; D011374:Progesterone; D011494:Protein Kinases; D017027:Protein Tyrosine Phosphatases; D002118:Calcium
keywords: acrosome reaction; calcium influx; human spermatozoa; kinases; phosphatases