Regulation of Sperm Function by Protein Phosphorylation

蛋白质磷酸化调节精子功能

• 批准号: 6990583
• 负责人: SRINIVASAN VIJAYARAGHAVAN
• 金额: $ 31.61万
• 依托单位: KENT STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-12-01 至 2009-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6990583
• 关键词: acidity /alkalinity; calcium ion; cilium /flagellum motility; cyclic AMP; enzyme activity; flagellum; immunoprecipitation; isozymes; phosphoprotein phosphatase; phosphoproteins; phosphorylation; protein kinase; recombinant proteins; sperm; sperm motility

DESCRIPTION (provided by applicant): A long-term goal of my laboratory is to understand the biochemical mechanisms underlying sperm motility and fertilization. In spermatozoa, where little protein synthesis occurs, protein phosphorylation is a major mechanism for regulating cellular functions. While it is known that changes in protein phosphorylation control motility initiation and fertilization, our knowledge of signaling pathways regulating these changes is limited. This proposal centers on a signaling enzyme in spermatozoa, the serine/threonine phosphatase PP1gamma2. It is a key enzyme in spermatogenesis and regulation of mature sperm function. Knowing how this enzyme works at the biochemical and molecular levels will contribute to our understanding of male gamete function. Protein purification and sequencing have enabled us to identify a number of potential PP1gamma2 binding and regulatory proteins. Immunoprecipitation and binding studies with recombinant proteins showed that two of these regulatory proteins are sds22 and protein 14-3-3 - discovered for the first time in spermatozoa. These polypeptides, which have critical functions in somatic cells, have novel roles in regulating male gamete function. In addition to changes in its binding to regulatory proteins, PP1gamma2 phosphorylation is increased during sperm maturation in the epididymis. The central hypothesis in this proposal is that the regulated action of PP1gamma2 is critical for sperm maturation, motility initiation, and other essential sperm functions. We will use biochemical and molecular approaches to characterize, at the mechanistic level, how phosphorylation and binding interactions between PP1gamma2 and its regulatory proteins relate to sperm motility and fertilizing ability. Aside from its basic importance to male gamete biology, this study has potential applications in the diagnosis and treatment of male infertility and in the development of novel approaches to male contraception.

描述（由申请人提供）：我实验室的长期目标是了解精子活力和受精的生化机制。在精子中，蛋白质合成很少，蛋白质磷酸化是调节细胞功能的主要机制。虽然众所周知，蛋白质磷酸化的变化控制运动起始和受精，但我们对调节这些变化的信号通路的了解有限。 该提案的重点是精子中的一种信号酶，即丝氨酸/苏氨酸磷酸酶 PP1gamma2。它是精子发生和成熟精子功能调节的关键酶。了解这种酶在生化和分子水平上的工作原理将有助于我们了解雄配子功能。蛋白质纯化和测序使我们能够鉴定出许多潜在的 PP1gamma2 结合和调节蛋白。重组蛋白的免疫沉淀和结合研究表明，其中两种调节蛋白是 sds22 和蛋白 14-3-3，这是首次在精子中发现的。这些多肽在体细胞中具有关键功能，在调节雄配子功能方面具有新的作用。除了与调节蛋白的结合发生变化外，PP1gamma2 磷酸化在附睾中的精子成熟过程中也会增加。 该提案的中心假设是 PP1gamma2 的调节作用对于精子成熟、运动启动和其他基本精子功能至关重要。我们将使用生化和分子方法在机制水平上表征 PP1gamma2 及其调节蛋白之间的磷酸化和结合相互作用如何与精子活力和受精能力相关。除了对雄性配子生物学具有基本重要性外，这项研究在男性不育症的诊断和治疗以及开发男性避孕新方法方面也具有潜在的应用。