Regulators of the sperm acrosome reaction

描述(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带结合，并在与卵子融合之前完成顶体反应。透明带通过TRPC阳离子通道触发钙离子进入精子，从而启动顶体反应。然而，将钙信号耦合到顶体反应的最终事件的下游机制却知之甚少，这是我们对受精理解的一个重大差距。 我们在精子中发现了一种新的TRPC结合蛋白Enkurin。该项目的目的是阐明enkurin在精子功能中的作用。该项目这一阶段的工作假设是，enkurin是一个适配器，通过将调节分子拴在TRPC通道上来发挥作用，这些调节分子在启动顶体反应中发挥关键作用。这些假说将在下列实验中得到验证：(I)定位TRPC通道的enkurin上的相互作用位点和介导结合和功能活性的调节激酶；(Ii)确定精子中激活的调节激酶的产物；(Iii)确定enkurin/激酶激活在控制顶体反应中的下游后果；(Iv)确定enkurin调节TRPC离子通道活性的机制；以及(V)确定enkurin在转基因小鼠中的作用机制。 这些研究在两个方面是相关的。首先，它们可能会促进我们对生殖过程中至关重要的一步的基本理解。其次，这些研究可能会对人类不孕不育的治疗和新避孕药的设计产生治疗效果。

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.