US-Mexico Cooperative Research: cGMP Regulated Ionic Channels in Sperm

该奖项将支持华盛顿大学的Bennett Shapiro教授与墨西哥城文萨多研究中心(CINVESTAV)的Alberto Darszon教授进行研究合作。研究人员打算探索海胆精子对同一物种的卵子产生反应的机制。众所周知，从卵子扩散到精子表面的多肽会导致精子改变一些超细胞参数。这些肽可能起到趋化作用，还能引起超细胞内ı、钙离子的一过性升高！和ıcemp！初步数据表明，精子质膜上存在依赖cGMP的钙通道。这种通道的可能候选者将被提纯，并在重组的双层系统中探索它们的特征。这种通道可能是精子趋化性信号转导通路的组成部分；对其性质的分析可能会阐明负责光传导的类比通道的机制。海胆精子具有一些独特的优势，而且细胞类型更复杂，是化学迁移的基本模型。许多与细胞周期、生长和分化有关的细胞活动在精子中是不存在的。这种未分裂细胞的新陈代谢被放大，它对趋化作用的刺激有限，这与大肠杆菌形成鲜明对比，大肠杆菌对大量的引诱剂和驱避剂产生反应，并活跃地生长和分裂。因此，这种专注于新陈代谢的单精子阵列使研究人员能够揭示趋化作用途径中的一些生化机制。通过结合Mexian小组在平面双层研究中对膜蛋白通道重建特别感兴趣的优势，以及美国小组在调节细胞行为的纯化蛋白功能研究方面的经验，这项研究有可能增加我们对精子趋化性和卵子-精子相互作用的理解。

This award will support Prof. Bennett Shapiro of the University of Washington in a research collaboration with Prof. Alberto Darszon of the Centro de Investigacrones y Estudios Avanzador (CINVESTAV) in Mexico City. The reserarchers intend to explore the mechanism whereby sea urchinsperm respond to eggs of the same species. It is known that peptides that diffuse from the egg to bind at the sperm surface cause the sperm to alter several ultra cellular parameters. The pepticles may play a chemotactic role and also cause transient elevations in ultracellular ıCa2+! and ıcEMP!. Preliminary data suggests the presence of a cGMP- dependent Ca2+ chfannel in plasma membranes from the sperm. Possible candidates for such a channel will be purified and their characteristics explored in reconstituted bilayer systems. Such a channel may be a component of the signal tranduction pathway of sperm chemotaxis; an analysis of its properties may clarify the mechanism of the analogoris channel that is responsible for photo transduction.l The sea urchin sperm offers some distinct advantages one more complex cell types as a basic model for chemostraxis. Many of the superflous (in this context) cellular activities related to the cell cycle, growth, and differentiation are absent from the spermitozoan. The amplified metabolism of this non-dividing cell and its limited stimulus for chemotaxis are in contrast to E. coli, which respond to a host of attractants and repellants and are actively growing and dividing. Thus the metabolically mono focused sperm array allow researchers to unearth some biochemical mechanism in the pathway of chemotaxis. By combing the strengthsof the Mexian group in planar bilayer studies with special interests in the recoinstitution of membraneprotein channels, with the experience of the U.S. group in functional studies of purified proteins that mediato cellular behavior, this study has the potential to increase our understanding of sperm chemotaxis and egg-sperm interaction.