Calmodulin signals capacitation and triggers the agonist-induced acrosome reaction in mouse spermatozoa
Calmodulin signals capacitation and triggers the agonist-induced acrosome reaction in mouse spermatozoa
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DOI：
10.1006/abbi.2001.2364
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发表时间：
2001-06-01
影响因子：
3.9
通讯作者：
Tulsiani, DRP
中科院分区：
文献类型：
--
作者：
Bendahmane, M;Lynch, C;Tulsiani, DRP
有能力的顶体完整精子与新糖蛋白（ngps）或溶解的透明带（ZP）（卵子的细胞外糖萼）上的特定糖残基相互作用，然后启动信号转导级联，导致精子质膜和顶体外膜在多个位点开窗和融合以及顶体内容物的胞吐（即顶体的诱导）反应（AR））。 AR 在精子结合位点释放顶体内容物，被认为是精子穿透 ZP 并使卵子受精的先决条件。由于 Ca2+/钙调蛋白 (CaM) 在多种细胞信号传导途径和膜融合事件中发挥重要作用，因此我们使用药理学方法来研究 CaM（一种钙结合蛋白）在精子获能和激动剂诱导的 AR 中的作用。在体外获能培养基中或在精子获能后加入 CaM 拮抗剂（钙调蛋白结合域、卡米达唑、化合物 48/80、ophiobolin A、W5、W7 和 W13）可阻断 npg-/ZP 诱导的 AR。纯化的 CaM 在很大程度上逆转了获能过程中拮抗剂的 AR 阻断作用。我们的结果表明，CaM 在小鼠精子的启动（即获能）以及激动剂诱导的 AR 中发挥着重要作用。这些数据使我们能够提出 CaM 通过调节精子膜成分来调节这些事件。 (C) 2001 年学术出版社。
Capacitated acrosome-intact spermatozoa interact with specific sugar residues on neoglycoproteins (ngps) or solubilized zona pellucida (ZP), the egg's extracellular glycocalyx, prior to the initiation of a signal transduction cascade that results in the fenestration and fusion of the sperm plasma membrane and the outer acrosomal membrane at multiple sites and exocytosis of acrosomal contents (i.e., induction of the acrosome reaction (AR)). The AR releases acrosomal contents at the site of spermzona binding and is thought to be a prerequisite event that allows spermatozoa to penetrate the ZP and fertilize the egg. Since Ca2+/calmodulin (CaM) plays a significant role in several cell signaling pathways and membrane fusion events, we have used a pharmacological approach to examine the role of CaM, a calcium-binding protein, in sperm capacitation and agonist-induced AR. Inclusion of CaM antagonists (calmodulin binding domain, calmidazolium, compound 48/80, ophiobolin A, W5, W7, and W13), either in in vitro capacitation medium or after sperm capacitation blocked the npg-/ZP-induced AR. Purified CaM largely reversed the AR blocking effects of antagonists during capacitation. Our results demonstrate that CaM plays an important role in priming (i.e., capacitation) of mouse spermatozoa as well as in the agonist-induced AR. These data allow us to propose that CaM regulates these events by modulating sperm membrane component(s). (C) 2001 Academic Press.