蛋白质棕榈酰化是指饱和十六碳的棕榈酸盐通过硫酯键或者酰胺键连接在蛋白质肽链的半胱氨酸上,属翻译后修饰,可影响蛋白质的相互作用、稳定性及定位等功能。热休克蛋白90(heat shock protein 90,Hsp90)是一种重要的分子伴侣,已证明其参与精子获能等生理过程。然而,哺乳动物精子中是否存在蛋白质棕榈酰化,Hsp90在精子不同生理状态下是否发生棕榈酰化,目前尚不清楚。本研究首先采用酰基-生物素置换法检测小鼠附睾尾部成熟精子总蛋白质棕榈酰化情况,然后通过CSS-Palm 4.0软件预测Hsp90的棕榈酰化位点,再进一步结合免疫沉淀方法检测附睾头部、附睾尾部精子的Hsp90棕榈酰化情况。结果显示,小鼠附睾尾部精子多种蛋白质存在棕榈酰化,其中分子量大小约50、65、72、85和130 k Da的蛋白质发生棕榈酰化最为显著;软件预测显示Hsp90两个亚型共有5个棕榈酰化位点;免疫沉淀结果也显示小鼠精子存在棕榈酰化的Hsp90,且其棕榈酰化水平与小鼠精子的生理状态有关:附睾尾部棕榈酰化水平比附睾头部高,而获能后的棕榈酰化水平比获能前明显升高。以上结果表明,哺乳动物精子中存在蛋白棕榈酰化,且Hsp90棕榈酰化可能参与精子生理状态的调节。
Once the sperm enters into the female reproductive tract,they undergo an important process called capacitation,which involves a series of physiological and biochemical changes that ensure fertilization.During capacitation,calcium ions(Ca^(2+))increase the bending amplitude of a sperm’s flagellum.This causes hyperactivation,which is manifested as the asymmetrical beating of the flagellum.Tyrosine phosphorylation is also a cause for human sperm hyperactivation;asthenospermia—that is,reduced sperm motility—occurs when the sperm are incapable of hyperactivation owing to impaired tyrosine phosphorylation.[1]Hyperactivated motility enables the sperm to migrate and penetrate the cumulus cells and zona pellucida surrounding the oocyte,leading to fertilization.Therefore,the hyperactivated motility of sperm is critical for male reproductive ability,and the molecular mechanism underlying human sperm hyperactivation requires discussion.
Ya-Yan WangPei-Bei SunKun LiTian GaoDong-Wang ZhengFang-Ping WuA-juan LiuYa Ni
