title: Sperm binding glycoprotein (SBG) produces calcium and bicarbonate dependent alteration of acrosome morphology and protein tyrosine phosphorylation on boar sperm.
abstract: The oviduct is a dynamic organ which modulates gamete physiology. Two subpopulations of sperm have been described in the oviduct of sows, a majority with normal appearance in the deep furrows and a minority, centrally located, and showing damaged membranes. Sperm-oviduct interaction provides the formation of a sperm storage and allows the selection of sperm with certain qualities. Pig (Sus scrofa) oviductal sperm binding glycoprotein (SBG) binds to sperm and exposes Gal beta1-3GalNAc. This disaccharide may be recognized by boar spermadhesin AQN1, which seems to be involved in sperm interaction with the oviduct. SBG is present at the apical surface of the epithelial cells that surround the lumen of the oviduct rather than at the bottom of the crypts. These characteristics imply it could be involved in sperm interaction with this organ. In this study, we evaluate the effect of SBG over boar sperm. We show that the presence of SBG produces alterations of the acrosome morphology of sperm only when they are incubated in capacitating conditions. SBG binds to the periacrosomal region of sperm undergoing capacitation. Its presence induces an increase on the tyrosine-phosphorylation of a polypeptide of apparent molecular mass 97 kDa, as occurs with a 95 kDa protein in other mammalian sperm upon acrosomic reaction. Altogether, these results suggest that SBG might be involved in sperm selection by alteration of the acrosome of sperm that have already begun the capacitation process when they arrive to the oviduct.
authors.affiliation: División Biología del Desarrollo, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET) Rosario, Santa Fe, Argentina.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Teijeiro
authors.forename: Marcelo O
authors.initials: MO
authors.lastname: Cabada
authors.forename: Patricia E
authors.initials: PE
authors.lastname: Marini
mesh_terms: D000177:Acrosome / Q000378:metabolism*; D000818:Animals; D004187:Disaccharides / Q000378:metabolism; D005260:Female; D006023:Glycoproteins / Q000378:metabolism*; D008297:Male; D010057:Oviducts / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D029589:Seminal Plasma Proteins / Q000378:metabolism* / Q000494:pharmacology; D013075:Sperm Capacitation / Q000187:drug effects / Q000502:physiology*; D034421:Sus scrofa / Q000378:metabolism*