Potential involvement of several signaling pathways in initiation of the chicken acrosome reaction.
Avian sperm biology has demonstrated specific features in preparation for fertilization. For example, capacitationlike processes and motility hyperactivation do not exist in the form described in mammals. The present study investigated the potential involvement of several signaling pathways, including protein kinase A (PKA), phosphatidylinositol 3 kinase (PIK3), mitogen-activated protein kinase 3/1 (MAPK3/1), and MAPK14 in the chicken acrosome reaction (AR). The presence in chicken spermatozoa of key proteins involved in these signaling pathways (i.e., cAMP-responsive element-binding protein [CREB], AKT, MAPK1, and MAPK14 and their respective phosphorylated forms) was detected using immunoblotting and localized by immunocytochemistry, mainly in the heads. The potential involvement of these pathways in the AR induced by inner perivitelline layer (IPVL) and Ca(2+) was then examined using specific inhibitors and phosphorylation status measurements. The effects of the specific inhibitors on motility were also measured. Phosphorylations of AKT, CREB, and MAPK1, but not MAPK14, were increased at the time of AR. Phosphorylation of AKT was increased in the presence of IPVL alone, whereas both IPVL and Ca(2+) were needed to increase CREB and MAPK1 phosphorylations. Inhibition of the three corresponding pathways blocked the increase in phosphorylation and significantly decreased AR. Inhibitions of the PKA and MAPK1 pathways also significantly decreased motility, whereas MAPK14 and PIK3 inhibition had no effect on motility. Our results suggest that the AR could be mediated by activation of the PKA, PIK3, and MAPK1 pathways through a sequential action involving, successively, PIK3 and then PKA and MAPK1 activations.
Lemoine
Manuela
M
Institut National de la Recherche Agronomique, UMR85, Physiologie de la Reproduction et des Comportements, Nouzilly, France.
Dupont
Joëlle
J
Guillory
Vanaïque
V
Tesseraud
Sophie
S
Blesbois
Elisabeth
E
D020101:Acrosome Reaction; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D004791:Enzyme Inhibitors; D005260:Female; D020935:MAP Kinase Signaling System; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048308:Mitogen-Activated Protein Kinase 14 / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D013081:Sperm Motility; D013094:Spermatozoa / Q000201:enzymology
D017362:Cyclic AMP Response Element-Binding Protein; D004791:Enzyme Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048308:Mitogen-Activated Protein Kinase 14