Calcium/calmodulin and cAMP/protein kinase-A pathways regulate sperm motility in the stallion.
In spite of the importance of sperm motility to fertility in the stallion, little is known about the signaling pathways that regulate motility in this species. In other mammals, calcium/calmodulin signaling and the cyclic AMP/protein kinase-A pathway are involved in sperm motility regulation. We hypothesized that these pathways also were involved in the regulation of sperm motility in the stallion. Using immunoblotting, calmodulin and the calmodulin-dependent protein kinase II β were shown to be present in stallion sperm and with indirect immunofluorescence calmodulin was localized to the acrosome and flagellar principal piece. Additionally, inhibition of either calmodulin or protein kinase-A significantly reduced sperm motility without affecting viability. Following inhibition of calmodulin, motility was not restored with agonists of the cyclic AMP/protein kinase-A pathway. These data suggest that calcium/calmodulin and cyclic AMP/protein kinase-A pathways are involved in the regulation of stallion sperm motility. The failure of cyclic AMP/protein kinase-A agonists to restore motility of calmodulin inhibited sperm suggests that both pathways may be required to support normal motility.
Department of Clinical Studies, New Bolton Center, University of Pennsylvania School of Veterinary Medicine, 382 West Street Rd., Kennett Square, PA 19348, USA.
Jodi
J
Lasko
Karen
K
Schlingmann
Ann
A
Klocke
Grace Ann
GA
Mengel
Regina
R
Turner
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000235:genetics / Q000378:metabolism; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D006736:Horses / Q000502:physiology*; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D013081:Sperm Motility / Q000502:physiology; D013094:Spermatozoa / Q000201:enzymology / Q000502:physiology*; D013449:Sulfonamides / Q000494:pharmacology
D002147:Calmodulin; D007546:Isoquinolines; D013449:Sulfonamides; C017967:W 7; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D002118:Calcium