Ganglioside GM1 Mediates Decapacitation Effects of SVS2 on Murine Spermatozoa
Ganglioside GM1 Mediates Decapacitation Effects of SVS2 on Murine Spermatozoa
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DOI：
10.1095/biolreprod.108.069054
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发表时间：
2008-12-01
影响因子：
3.6
通讯作者：
Yoshida, Manabu
中科院分区：
文献类型：
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作者：
Kawano, Natsuko;Yoshida, Kaoru;Yoshida, Manabu
在受精之前，哺乳动物精子需要在雌性生殖道中获得可受精性（获能）。另一方面，获能的精子在用精浆处理时可逆地失去其获能状态（去能）。以前，我们证明了小鼠精浆蛋白，SVS2，是一种去激活因子，并调节精子在体内的可再生性。在这里，我们研究了SVS2调节可移植性的机制。获能似乎是介导的脂质筏的动态变化，因为在精子质膜的脂质筏的胆固醇成分的释放是必不可少的获能。当用霍乱毒素亚单位B（CT B）染色射出的精子时，精子的染色模式与SVS2的结合模式相同，所述霍乱毒素亚单位B（CT B）优选与脂筏的另一成员神经节苷脂GM 1相互作用。有趣的是，SVS2和CTB相互竞争性地结合到精子表面，这表明两种分子的结合靶点是相同的，即GM1。分子相互作用的研究，通过覆盖试验和石英晶体微天平分析表明，SVS2选择性地与GM1，而不是与其他神经节苷脂相互作用。此外，GM1的外部添加无效SVS2诱导的精子去激活。因此，神经节苷脂GM1是SVS2的受体，并在体内获能中起关键作用。
Prior to fertilization, mammalian spermatozoa need to acquire fertilizing ability (capacitation) in the female reproductive tract. On the other hand, capacitated spermatozoa reversibly lose their capacitated state when treated with seminal plasma (decapacitation). Previously, we demonstrated that a mouse seminal plasma protein, SVS2, is a decapacitation factor and regulates sperm fertilizing ability in vivo. Here, we examined the mechanisms of regulation of fertilizing ability by SVS2. Capacitation appears to be mediated by dynamic changes in lipid rafts since release of the cholesterol components of lipid rafts in the sperm plasma membrane is indispensable for capacitation. When the ejaculated spermatozoa were stained with a cholera toxin subunit B (CTB) that preferably interacts with ganglioside GM1, another member of the lipid rafts, the staining pattern of the sperm was the same as the binding pattern of SVS2. Interestingly, SVS2 and CTB competitively bound to the sperm surface with each other, suggesting that the binding targets of both molecules are the same, that is, GM1. Molecular interaction studies by the overlay assay and the quartz crystal microbalance analysis revealed that SVS2 selectively interacts with GM1 rather than with other gangliosides. Furthermore, external addition of GM1 nullified SVS2-induced sperm decapacitation. Thus, ganglioside GM1 is a receptor of SVS2 and plays a crucial role in capacitation in vivo.