Porcine oviduct sperm binding glycoprotein and its deleterious effect on sperm: a mechanism for negative selection of sperm?

Abstract

In their journey through the oviduct some subpopulations of sperm are preserved in a reservoir, while others are negatively selected. Sperm binding glycoprotein (SBG) is a pig oviductal epithelial cell glycoprotein that produces, under capacitating conditions, acrosome alteration, p97 tyrosine-phosphorylation and reduction of the motility of sperm. In this paper, we show that SBG is accessible at the extracellular surface of the oviductal epithelial cells, supporting a sperm interaction biological role in situ. We analyze the possible dependence of the tyrosine-phosphorylation of p97 on the PKA mechanism, fi nding that apparently it is not PKA dependent. Also, after SBG treatment the phosphorylated proteins locate mainly at the detached periacrosomal region and at the tail of sperm; the latter may be related to SBG's motility reduction effect. The study of the time course effect of SBG on sperm as detected by chlortetracycline (CTC) staining and of its binding to sperm by immunodetection in conjunction with CTC, shows results in agreement with the hypothesis that this glycoprotein is involved in the alteration of acrosomes in a specifi c sperm subpopulation. The results suggest that SBG may be part of a mechanism for negative selection of sperm.

Apical membranes prepared by peeling from whole porcine oviducts interact with homologous sperm

“…The possibility of preparing APM from a subpopulation of cells at specific locations and in their natural form is one of the advantages of the present method. The differences derived from the use of alternative experimental models are also noted between treatment of sperm with APM in this work and previous observations with purified SBG (Teijeiro et al 2008(Teijeiro et al , 2011.…”

“…Since interaction between sperm and the oviduct is mediated by a molecular complex (Talevi and Gualtieri 2010) and SBG is present in APM obtained by peeling, we decided to study the phosphorylation produced by SBG considering its molecular context, given by APM. Results show that APM produce a tyrosine phosphorylation pattern in sperm than differs from the one produced by purified SBG (Teijeiro et al 2008(Teijeiro et al , 2011, although phosphorylation of p97 is maintained. In these experiments, sperm proteins with apparent molecular masses of 92, 97, 210 and 220 kDa are phosphorylated after 2 h of incubation with APM.…”

“…Previous studies carried out by us demonstrated the tyrosine phosphorylation of a 97-kDa sperm protein by SBG, an apical membrane glycoprotein from oviductal epithelial cells (Teijeiro et al 2008(Teijeiro et al , 2011. Since interaction between sperm and the oviduct is mediated by a molecular complex (Talevi and Gualtieri 2010) and SBG is present in APM obtained by peeling, we decided to study the phosphorylation produced by SBG considering its molecular context, given by APM.…”

“…A further analysis of APM proteins showed that this fraction is enriched in SBG (Fig. 2b), a glycoprotein localized at the extracellular domain of oviductal epithelial cells from the lumen of the oviduct (Perez et al 2006;Teijeiro et al 2011) and the absence of Na + /K + -ATPase α1 polypeptide, indicating no detectable contamination with basolateral membranes (Fig. 2b).…”

“…In a further study, the glycoprotein showed effects on acrosome, motility and protein phosphorylation of homologous spermatozoa (Teijeiro et al 2008) and its localization (Perez et al 2006; Electronic supplementary material The online version of this article (doi:10.1007/s00441-012-1338-3) contains supplementary material, which is available to authorized users. Teijeiro et al 2011) and function were addressed (Teijeiro et al 2011). Another set of experiments using protein extracts from whole oviductal cell membranes but with specific technical modifications over our previous protocols, allowed us to describe the interaction between annexin A2 and sperm periacrosomal membranes in pig (Teijeiro et al 2009).…”