Regulators of the sperm acrosome reaction

描述（由申请人提供）：受精时精子和卵子的结合是生殖和发育的重要步骤。在哺乳动物中，包括人类，精子必须首先与卵子的透明外膜结合，并在与卵子融合之前完成顶体反应。透明质酸通过触发钙离子通过TRPC阳离子通道进入精子而启动顶体反应。然而，钙信号耦合到顶体反应的最终事件的下游机制知之甚少，代表了我们对受精理解的一个主要差距。 我们在精子中发现了一种新的TRPC结合蛋白enkurin。本项目的目的是阐明enkurin在精子功能中的作用。该项目这一阶段的工作假设是，enkurin是一种适配器，通过将调节分子束缚在TRPC通道上发挥作用，并且这些调节分子在顶体反应的启动中发挥重要作用。这些假设将在以下实验中进行测试：（i）绘制恩库蛋白上TRPC通道和介导结合和功能活性的调节激酶的相互作用位点;（ii）鉴定精子中活化的调节激酶的产物;（iii）确定恩库蛋白/激酶活化在控制顶体反应中的下游后果;（iv）确定恩库蛋白调节TRPC离子通道活性的机制;和（v）确定转基因小鼠中enkurin作用的机制。 这些研究在两个方面具有相关性。首先，它们可能会促进我们对生殖过程中一个重要步骤的基本理解。第二，这些研究在治疗人类不育症和设计新的避孕药方面可能会产生治疗效果。

DESCRIPTION (provided by applicant): The union of sperm and egg at fertilization is an essential step in reproduction and development. In mammals, including human, sperm must first bind to the egg's zona pellucida coat and complete the acrosome reaction before fusing with the egg. The zona pellucida initiates acrosome reactions by triggering the entry of calcium ions into sperm through TRPC cation channels. However, the downstream mechanisms that couple calcium signals into the final events of the acrosome reaction are poorly understood and represent a major gap in our understanding of fertilization. We discovered a novel TRPC binding protein, enkurin, in sperm. The objective of this project is to delineate the roles of enkurin in sperm function. The working hypotheses for this stage of the project is that enkurin is an adaptor that acts by tethering regulatory molecules to the TRPC channel, and that these regulatory molecules play essential roles in the initiation of the acrosome reaction. These hypotheses will be tested in experiments that: (i) map interaction sites on enkurin for TRPC channels and a regulatory kinase that mediate binding and functional activity; (ii) identify products of the activated regulatory kinase in sperm; (iii) determine the downstream consequences of enkurin/kinase activation in control of acrosome reactions; (iv) determine, the mechanism by which enkurin regulates TRPC ion channel activity; and (v) determine the mechanism of enkurin action in transgenic mice. These studies are relevant in two regards. First, they may advance our basic understanding of an essential step in the reproductive process. Second, there may be therapeutic consequences to these studies both with regard to the treatment of human infertility and for the design of new contraceptives.