title: Ca2+/Calmodulin-Dependent Protein Kinase Kinases (CaMKKs) Effects on AMP-Activated Protein Kinase (AMPK) Regulation of Chicken Sperm Functions.
abstract: Sperm require high levels of energy to ensure motility and acrosome reaction (AR) accomplishment. The AMP-activated protein kinase (AMPK) has been demonstrated to be strongly involved in the control of these properties. We address here the question of the potential role of calcium mobilization on AMPK activation and function in chicken sperm through the Ca(2+)/calmodulin-dependent protein kinase kinases (CaMKKs) mediated pathway. The presence of CaMKKs and their substrates CaMKI and CaMKIV was evaluated by western-blotting and indirect immunofluorescence. Sperm were incubated in presence or absence of extracellular Ca(2+), or of CaMKKs inhibitor (STO-609). Phosphorylations of AMPK, CaMKI, and CaMKIV, as well as sperm functions were evaluated. We demonstrate the presence of both CaMKKs (α and β), CaMKI and CaMKIV in chicken sperm. CaMKKα and CaMKI were localized in the acrosome, the midpiece, and at much lower fluorescence in the flagellum, whereas CaMKKβ was mostly localized in the flagellum and much less in the midpiece and the acrosome. CaMKIV was only present in the flagellum. The presence of extracellular calcium induced an increase in kinases phosphorylation and sperm activity. STO-609 reduced AMPK phosphorylation in the presence of extracellular Ca(2+) but not in its absence. STO-609 did not affect CaMKIV phosphorylation but decreased CaMKI phosphorylation and this inhibition was quicker in the presence of extracellular Ca(2+) than in its absence. STO-609 efficiently inhibited sperm motility and AR, both in the presence and absence of extracellular Ca(2+). Our results show for the first time the presence of CaMKKs (α and β) and one of its substrate, CaMKI in different subcellular compartments in germ cells, as well as the changes in the AMPK regulation pathway, sperm motility and AR related to Ca(2+) entry in sperm through the Ca(2+)/CaM/CaMKKs/CaMKI pathway. The Ca(2+)/CaMKKs/AMPK pathway is activated only under conditions of extracellular Ca(2+) entry in the cells.
authors.affiliation: INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France.|CNRS, UMR7247, F-37380 Nouzilly, France.|Université François Rabelais de Tours, F-37000 Tours, France.|IFCE, F-37380 Nouzilly, France.
authors.forename: Thi Mong Diep
authors.initials: TM
authors.lastname: Nguyen
authors.affiliation: INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France.|CNRS, UMR7247, F-37380 Nouzilly, France.|Université François Rabelais de Tours, F-37000 Tours, France.|IFCE, F-37380 Nouzilly, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Combarnous
authors.affiliation: INRA, Unité de Recherches Avicoles, F-37380 Nouzilly, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Praud
authors.affiliation: INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France.|CNRS, UMR7247, F-37380 Nouzilly, France.|Université François Rabelais de Tours, F-37000 Tours, France.|IFCE, F-37380 Nouzilly, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Duittoz
authors.affiliation: INRA, UMR85 Physiologie de la Reproduction et des Comportements, F-37380 Nouzilly, France.|CNRS, UMR7247, F-37380 Nouzilly, France.|Université François Rabelais de Tours, F-37000 Tours, France.|IFCE, F-37380 Nouzilly, France.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Blesbois
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D020101:Acrosome Reaction; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002645:Chickens; D008297:Male; D053644:Naphthalimides / Q000494:pharmacology; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013081:Sperm Motility; D013094:Spermatozoa / Q000502:physiology*; D013379:Substrate Specificity
chemical_list: D001562:Benzimidazoles; D053644:Naphthalimides; D047428:Protein Kinase Inhibitors; C458525:STO 609; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D055372:AMP-Activated Protein Kinases