Alteration of the ecto-protein phosphorylation profile of intact goat spermatozoa during epididymal maturation.
Intact cauda-epididymal mature and caput-epididymal immature goat spermatozoa were assessed for their capacity to phosphorylate the outer surface proteins upon incubation in a modified Ringer's solution containing [delta-32P]ATP. The immature spermatozoa possessed markedly greater (approximately 7-fold) efficacy to phosphorylate the ecto-proteins than the mature cells. Autoradiographic analysis of the 32P-labelled proteins resolved by SDS-PAGE, showed that multiple sperm ecto-proteins are phosphorylated by an endogenous ecto-cyclic AMP-independent protein kinase (CIK) and the phosphorylation profile of these proteins underwent marked alteration during the epididymal sperm maturation. The intact caput-sperm as well showed nearly 4-fold higher specific activity of ecto-CIK than the cauda-sperm when the kinase activity was estimated using phosvitin as the exogenous protein substrate. The data suggest that the ecto-CIK and its specific protein substrates located on the sperm outer-surface, may have important roles in regulating the epididymal maturation of the male gametes.
Mitra
S
S
Indian Institute of Chemical Biology, Jadavpur, Calcutta.
Majumder
G C
GC
D000818:Animals; D001345:Autoradiography; D004822:Epididymis / Q000166:cytology; D006041:Goats / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D013079:Sperm Maturation / Q000502:physiology; D013094:Spermatozoa / Q000378:metabolism*
D008565:Membrane Proteins; D011494:Protein Kinases