Protein tyrosine phosphorylation of a heparin-binding sperm membrane mitogen (HBSM) is associated with capacitation and acrosome reaction.
Protein tyrosine phosphorylation in spermatozoa is associated with epididymal maturation and though to be central for attainment of a capacitated state and expression of hyperactivated motility. Heparin, the most highly sulfated glycosaminoglycans, was also the most potent at stimulating the acrosomal reaction in bovine epididymal spermatozoa. Studies using radiolabeled inorganic phosphate showed 11-fold increase (32)Pi incorporation in heparin-binding sperm membrane protein (HBSM) during spermatozoal capacitation, and the phosphorylation occurs at the tyrosine residue. Epididymal spermatozoa were induced to undergo capacitation and acrosome reaction by 70% when the cells were incubated in BWW medium supplemented with heparin. The spermatozoa pre-treated with anti-HBSM antibody showed 46% reduction in the hyperactivated motility and lowers the acrosome reaction. This was confirms by measuring the hydrolysis of benzoyl-l-arginine ethyl ether (BAEE) by the acrosomal enzyme; acrosin. The preliminary finding suggests that HBSM may play an important role in the sperm capacitation and acrosome reaction.
Mor
Visesato
V
Gamete Immunology Laboratory, Indian Institute of Chemical Biology, 4 Raja S.C Mullick Road, Jadavpur, Kolkata 700032, W.B., India.
Das
Tapasi
T
Bhattacharjee
Maitreyi
M
Chatterjee
Tapati
T
D000177:Acrosome / Q000187:drug effects / Q000502:physiology*; D020101:Acrosome Reaction / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006041:Goats; D006493:Heparin / Q000008:administration & dosage*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D013075:Sperm Capacitation / Q000187:drug effects / Q000502:physiology*; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology*
D008565:Membrane Proteins; D006493:Heparin; D011505:Protein-Tyrosine Kinases; D020928:Mitogen-Activated Protein Kinases