MECHANISMS OF SIGNAL TRANSDUCTION IN SPERMATOZOA

精子信号转导机制

• 批准号: 6219089
• 负责人: GREGORY S. KOPF
• 金额: $ 1.44万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2000-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6219089
• 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处理成 调节精子功能的细胞内第二信使。 受精代表了一种优雅的细胞间通讯模式 以及细胞与细胞的相互作用。在所有哺乳动物中，最初的精子-卵子相互作用 发生在透明带(ZP)，这是一种由 正在生长的卵母细胞。在许多哺乳动物中，顶体完整的精子与 ZP是特定物种的，是精子的绝对先决条件 顶体胞吐，这是精子穿透的关键事件 ZP，精子与卵子质膜的结合和膜融合 导致卵子激活和植入前启动的事件 发展。 ZP介导的顶体胞吐与受体介导的相似 体细胞中的分泌过程。在鼠标中，有几个标准 支持这一观点：1)ZP糖蛋白，ZP3，是生理上的- 介导精子与ZP结合和诱导的相关配体 顶体胞吐，2)ZP3结合蛋白存在于血浆中 覆盖在顶体上的膜，表明精子拥有 互补ZP3受体，3)精子含异三聚体鸟嘌呤 核苷酸结合调节蛋白(G蛋白)，它们是信号 ZP3介导的顶体转导蛋白的调节作用 胞吐作用；4)ZP/ZP3引起精子phi和cAMP的变化 浓度，表明离子/第二信使变化发生在 对ZP3-受体相互作用的反应。这项建议涉及具体的 ZP/ZP3-精子膜G蛋白的动力学问题 影响导致顶体的信号转导的相互作用 胞吐。 细胞生物学和生化方法将被用来，1)表征 ZP/ZP3-精子膜动力学调节G蛋白介导的信号 转导，2)鉴定和表征生物化学成分 形成功能信号转导复合体，该复合体响应于 ZP/ZP3与精子膜的相互作用； 其中ZP/ZP3调控精子腺酰环化酶。 这些研究应该有助于更好地理解 哺乳动物受精的生物化学，并将提供一个工作模型 用来设计合理的治疗方法来促进或干预 精子与卵子的相互作用。