Effects of native human zona pellucida glycoproteins 3 and 4 on acrosome reaction and zona pellucida binding of human spermatozoa.
Acrosome reaction is crucial to the penetration of spermatozoa through the zona pellucida (ZP). Glycosylation of ZP glycoproteins is important in spermatozoa-ZP interaction. Human ZP glycoprotein-3 (ZP3) is believed to initiate acrosome reaction. Recently, human ZP4 was also implicated in inducing acrosome reaction. These studies were based on recombinant human ZP proteins with glycosylation different from their native counterparts. In the present study, the effects of native human ZP3 and ZP4 on acrosome reaction and spermatozoa-ZP binding were investigated. Native human ZP3 and ZP4 were immunoaffinity-purified. They induced acrosome reaction and inhibited spermatozoa-ZP binding time- and dose-dependently to different extents. These biological activities of human ZP3 and ZP4 depended partly on their glycosylation, with N-linked glycosylation contributing much more significantly than O-linked glycosylation. Studies with inhibitors showed that both human ZP3- and ZP4-induced acrosome reactions were protein kinase-C, protein tyrosine kinase, T-type Ca2+ channels, and extracellular Ca2+ dependent. G-protein also participated in human ZP3- but not in ZP4-induced acrosome reaction. On the other hand, protein kinase-A and L-type Ca2+ channels took part only in human ZP4-induced acrosome reaction. This manuscript describes for the first time the actions of purified native human ZP3 and ZP4 on acrosome reaction and spermatozoa-ZP binding.
Chiu
Philip C N
PC
Department of Obstetrics and Gynaecology, University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
Wong
Ben S T
BS
Chung
Man-Kin
MK
Lam
Kevin K W
KK
Pang
Ronald T K
RT
Lee
Kai-Fai
KF
Sumitro
S B
SB
Gupta
S K
SK
Yeung
William S B
WS
D020101:Acrosome Reaction; D004527:Egg Proteins / Q000502:physiology*; D005260:Female; D006031:Glycosylation; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000502:physiology*; D011494:Protein Kinases / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000502:physiology*; D015398:Signal Transduction; D013094:Spermatozoa / Q000502:physiology*; D015044:Zona Pellucida / Q000502:physiology*; D000072216:Zona Pellucida Glycoproteins
D004527:Egg Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C000606517:ZP3 protein, human; D000072216:Zona Pellucida Glycoproteins; D011494:Protein Kinases