MECHANISMS OF SIGNAL TRANSDUCTION IN SPERMATOZOA

精子信号转导机制

• 批准号: 6271959
• 负责人: GREGORY S. KOPF
• 金额: $ 32.08万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-01 至 1999-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6271959
• 关键词: adenylate cyclase; biological signal transduction; cyclic AMP; molecular cloning; phosphoprotein phosphatase; phosphorylation; protein kinase A; protein tyrosine kinase; reproduction; sperm; sperm capacitation

The long-term objectives of the research plan are to elucidate the mechanisms by which mammalian sperm process extracellular messages into intracellular second messengers which modulate sperm function. Fertilization represents an elegant model of intercellular communication and cell-cell interaction. In all mammals, initial sperm-egg interaction occurs at the zona pellucida (ZP), an extracellular matrix synthesized by the growing oocyte. In many mammals, binding of acrosome-intact sperm to the ZP is species-specific and is an absolute prerequisite for sperm acrosomal exocytosis, an event which is critical for sperm penetration of the ZP, sperm binding to the egg plasma membrane, and membrane fusion events leading to egg activation and the initiation of preimplantation development. ZP-mediated acrosomal exocytosis has similarities to receptor-mediated secretory processes in somatic cells. In the mouse, several criteria support this idea: 1) the ZP glycoprotein, ZP3, is the physiologically- relevant ligand that mediates both sperm binding to the ZP and induces acrosomal exocytosis, 2) ZP3 binding proteins are present on the plasma membrane overlying the acrosome, suggesting that sperm possess complementary ZP3 receptors, 3) sperm contain heterotrimeric guanine nucleotide binding regulatory proteins (G proteins), which are signal transducing proteins that play a regulatory role in ZP3-mediated acrosomal exocytosis, and 4) ZP/ZP3 cause changes in sperm pHi and cAMP concentrations, suggesting that ionic/second messenger changes occur in response to ZP3-receptor interactions. this proposal addresses specific questions related to the dynamics of ZP/ZP3-sperm membrane-G protein interaction that effect signal transduction leading to acrosomal exocytosis. Cell biological and biochemical approaches will be used to, 1) characterize ZP/ZP3-sperm membrane dynamics regulating G protein-mediated signal transduction, 2) identify and characterize the biochemical components that form the functional signal transduction complex which forms in response to ZP/ZP3-sperm membrane interaction, and 3) characterize the mechanism by which ZP/ZP3 regulates the sperm adenylyl cyclase. These studies should contribute to a greater understanding of the biochemistry of mammalian fertilization and will provide a working model with which to design rational therapies for the promotion or intervention of sperm-egg interaction.

研究计划的长期目标是阐明 哺乳动物精子将细胞外信息加工成 调节精子功能的细胞内第二信使。 受精是细胞间通讯的一个极好的模型 和细胞间的相互作用。 在所有哺乳动物中，最初的精卵相互作用 发生在透明质膜（ZP），一种由细胞外基质合成的细胞外基质， 生长中的卵母细胞 在许多哺乳动物中，顶体完整的精子与 ZP是物种特异性的，是精子的绝对先决条件 顶体胞吐，这是一个事件，这是至关重要的精子穿透 ZP、精子与卵质膜的结合以及膜融合 导致卵子激活和着床前发育的事件 发展 ZP介导的顶体胞吐作用与受体介导的顶体胞吐作用相似， 体细胞的分泌过程。 在小鼠中， 支持这一观点：1）ZP糖蛋白，ZP 3，是生理上- 相关配体介导精子与ZP结合，并诱导 顶体胞吐，2）ZP 3结合蛋白存在于血浆中 膜覆盖顶体，表明精子具有 互补ZP 3受体，3）精子含有异源三聚体鸟嘌呤 核苷酸结合调节蛋白（G蛋白），其是信号传导蛋白。 在ZP 3介导的顶体中起调节作用的转导蛋白 ZP/ZP 3引起精子pHi和cAMP的变化 浓度，表明离子/第二信使的变化发生在 对ZP 3受体相互作用的反应。 该提案针对具体 与ZP/ZP 3-精子膜-G蛋白动力学相关的问题 相互作用影响信号转导，导致顶体 胞吐作用 细胞生物学和生物化学方法将用于：1）表征 ZP/ZP 3-精子膜动力学调节G蛋白介导的信号 转导，2）鉴定和表征 形成功能性信号转导复合物， ZP/ZP 3-精子膜相互作用，以及3）通过以下方式表征机制： 其中ZP/ZP 3调节精子腺苷酸环化酶。 这些研究应有助于更好地了解 哺乳动物受精的生物化学，并将提供一个工作模型 设计合理的治疗方法来促进或干预 精子和卵子的相互作用。