Binding of pig sperm receptor in the zona pellucida to the boar sperm acrosome.
Pig zona pellucida (ZP) contains three families of glycoproteins: PZP2, PZP3 alpha and PZP3 beta. PZP3 alpha mediates the binding of the ZP to spermatozoa. In this study, the binding site of pig ZP on boar spermatozoa and the zona-binding proteins of boar spermatozoa were studied using chemically modified zona glycoproteins or anti-pig ZP antiserum. Endo-beta-galactosidase-digested PZP3 alpha (E beta G-PZP3 alpha), which is deficient in sulfated N-acetylpolyactosamine, as well as solubilized ZP, bound to the acrosomal region of acrosome-damaged or partially acrosome-reacted spermatozoa. However, they did not bind to acrosome-intact or fully acrosome-reacted spermatozoa. Solubilized ZP did bind to the acrosomal cap released upon acrosome reaction. In western blot analyses, E beta G-PZP3 alpha bound to the sperm proteins with molecular masses similar to proacrosin-acrosin and the binding was inhibited by fucoidan and anti-pig acrosin antiserum. These results suggest that the binding site of solubilized pig ZP and E beta G-PZP3 alpha on spermatozoa is located mainly in the acrosomal matrix and on the membranous compartments in the acrosome and suggest that E beta G-PZP3 alpha binds to proacrosin-acrosin. The binding of E beta G-PZP3 alpha to proacrosin-acrosin may be involved in the binding of the ZP to the acrosome of partially acrosome-reacted spermatozoa.
Yonezawa
N
N
Department of Chemistry, Faculty of Science, Chiba University, Japan.
Hatanaka
Y
Y
Takeyama
H
H
Nakano
M
M
D000177:Acrosome / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D004527:Egg Proteins / Q000302:isolation & purification / Q000378:metabolism*; D005260:Female; D006651:Histocytochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000302:isolation & purification / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013084:Sperm-Ovum Interactions; D013552:Swine / Q000378:metabolism*; D015044:Zona Pellucida / Q000378:metabolism*; D000072216:Zona Pellucida Glycoproteins
D004527:Egg Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins