Decreased binding of calmodulin to bull sperm proteins during heparin-induced capacitation.
The 125I-calmodulin gel overlay procedure was used to evaluate the effect of a heparin treatment on the calmodulin-binding proteins of bull spermatozoa. At concentrations that increase the in vitro fertilization rate of in vitro-matured oocytes, heparin induced a decrease in the binding to calmodulin (CaM) in 3 sperm proteins of 28, 30, and 49 kDa. The binding of these proteins to CaM was higher when Ca2+ was absent from the overlay procedure, and this binding was negatively correlated to the fertilization rate. These results suggest that sperm capacitation is associated with a decrease in the binding of CaM to the 28, 30, and 49 kDa sperm CaM-binding proteins. Implications of such a decrease are discussed.
Leclerc
P
P
Ontogénie et Reproduction, Centre de Recherches du CHUL, Ste-Foy, Québec, Canada.
Sirard
M A
MA
Chafouleas
J G
JG
Lambert
R D
RD
D000818:Animals; D002147:Calmodulin / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D005306:Fertilization / Q000187:drug effects; D006493:Heparin / Q000494:pharmacology*; D008297:Male; D029589:Seminal Plasma Proteins; D013075:Sperm Capacitation / Q000187:drug effects*
D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D002352:Carrier Proteins; D029589:Seminal Plasma Proteins; C425042:spermadhesin; D006493:Heparin