Annexins Are Candidate Oviductal Receptors for Bovine Sperm Surface Proteins and Thus May Serve to Hold Bovine Sperm in the Oviductal Reservoir1

Abstract

The sperm of eutherian mammals are held in a storage reservoir in the caudal segment of the oviduct by binding to the mucosal epithelium. The reservoir serves to maintain the fertility of sperm during storage and to reduce the incidence of polyspermic fertilization. Bovine sperm bind to the epithelium via seminal vesicle secretory proteins in the bovine seminal plasma protein (BSP) family, namely, PDC109 (BSPA1/A2), BSPA3, and BSP30K, which coat the sperm head. Our objective was to identify the receptors for bull sperm on the oviductal epithelium. Proteins extracted from apical plasma membrane preparations of bovine oviductal epithelium were subjected to affinity purification using purified BSPs bound to corresponding antibodies conjugated to Protein A agarose beads. Oviductal protein bands of approximately 34 and 36 kDa were eluted by EGTA from the beads and identified by tandem mass spectrometry as annexins (ANXAs) 1, 2, 4, and 5. Subsequently, antibodies to each of the ANXAs were found to inhibit sperm binding to explants of oviductal epithelium. Anti-ANXA antibodies labeled the apical surfaces and cilia of the mucosal epithelium in sections of bovine oviduct. Western blots confirmed the presence of ANXAs in apical plasma membranes. Because fucose had been determined to be a critical component of the oviductal receptor, the ANXAs were immunoprecipitated from solubilized apical plasma membranes and were probed with Lotus tetragonolobus lectin to verify the presence of fucose. Thus, these ANXAs are strong candidates for the sperm receptors on bovine oviductal epithelium.

A Role for Acp29AB, a Predicted Seminal Fluid Lectin, in Female Sperm Storage inDrosophila melanogaster

“…involved in the establishment and maintenance of the oviductal sperm reservoir in mammals (Suarez 2002;Ekhlasi-Hundrieser et al 2005;Ignotz et al 2007).…”

“…Carbohydrates mediate the adherence of sperm to the epithelium, with different sugars playing important roles in different species (e.g., Demott et al 1995;Lefebvre et al 1995Lefebvre et al , 1997Ekhlasi-Hundrieser et al 2005). In cows, for example, biochemical studies suggest that fucose residues on oviductal annexins act as receptors for sperm, with several sperm-bound seminal proteins recognizing the fucose moiety (Ignotz et al 2001(Ignotz et al , 2007Gwathmey et al 2006).…”

The endocannabinoid system in bull sperm and bovine oviductal epithelium: role of anandamide in sperm–oviduct interaction

“…In addition, Gwathmey et al (2003) have demonstrated that bovine plasma seminal protein PDC-109 promotes bull sperm binding to oviduct epithelium in vitro and that it could be involved in the formation of the oviduct reservoir. Recently, Ignotz et al (2007) found that annexins (that contain fucose residues) might be possible candidates for sperm receptors on bovine oviductal epithelium. Besides, it is known that sulfated glycoconjugates are powerful inducers of sperm release in vitro possibly by promoting sperm capacitation (Gualtieri et al 2005) and/or disrupting the binding of bovine seminal plasma protein to annexins (Ignotz et al 2007).…”

“…Recently, Ignotz et al (2007) found that annexins (that contain fucose residues) might be possible candidates for sperm receptors on bovine oviductal epithelium. Besides, it is known that sulfated glycoconjugates are powerful inducers of sperm release in vitro possibly by promoting sperm capacitation (Gualtieri et al 2005) and/or disrupting the binding of bovine seminal plasma protein to annexins (Ignotz et al 2007).…”

Expression and putative function of fibronectin and its receptor (integrin α5β1) in male and female gametes during bovine fertilization in vitro

“…Although a considerable amount of knowledge has been gained especially in human and mouse (Almeida et al 1995, Bronson & Fusi 1996, Fusi et al 1996a, 1996b, Nixon et al 2007, Vjugina & Evans 2008, the exact mechanisms of the molecules involved in bovine fertilization are not unequivocally identified at present. Carbohydrates and glycoproteins are assumed to modulate adhesion and binding events during consecutive reproductive processes, like sperm-oviduct adhesion (Lefebvre et al 1997, Suarez et al 1998, Revah et al 2000, Talevi & Gualtieri 2001, Sostaric et al 2005, Ignotz et al 2007, sperm-oocyte interactions (Tulsiani et al 1997, Gougoulidis et al 1999, Amari et al 2001, Tanghe et al 2004a, 2004b, and embryo implantation (Whyte & Allen 1985, Biermann et al 1997.…”