ACTIVATION OF A G-PROTEIN COMPLEX BY AGGREGATION OF BETA-1,4-GALACTOSYLTRANSFERASE ON THE SURFACE OF SPERM

被引：151

作者：

GONG, XH ^{[1
]}

DUBOIS, DH ^{[1
]}

MILLER, DJ ^{[1
]}

SHUR, BD ^{[1
]}

机构：

[1] UNIV TEXAS, MD ANDERSON CANC CTR, DEPT BIOCHEM & MOLEC BIOL, HOUSTON, TX 77030 USA

来源：

SCIENCE | 1995年 / 269卷 / 5231期

关键词：

D O I：

10.1126/science.7569899

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Fertilization is initialed by the species-specific binding of sperm to the extracellular coat of the egg. One sperm receptor for the mouse egg is beta-1,4-galactosyltransferase (GalTase), which binds O-linked oligosaccharides on the egg coat glycoprotein ZP3. ZP3 binding induces acrosomal exocytosis through the activation of a pertussis toxin-sensitive heterotrimeric guanine nucleotide-binding protein (G protein). The cytoplasmic domain of sperm surface GalTase bound to and activated a heterotrimeric G protein complex that contained the G(i alpha) subunit. Aggregation of GalTase by multivalent ligands elicited G protein activation. Sperm from transgenic mice that overexpressed GalTase had higher rates of G protein activation than did wild-type sperm, which rendered transgenic sperm hypersensitive to their ZP3 ligand. Thus, the cytoplasmic domain of cell surface GalTase appears to enable it to function as a signal-transducing receptor for extracellular oligosaccharide ligands.

引用

页码：1718 / 1721

页数：4