SPERM GLYCINE RECEPTOR AND ZONA-INITIATED EXOCYTOSIS

描述（改编自研究者摘要）：本修订版 一项提案探讨了一种假定的甘氨酸受体（GlyR）的作用， 在哺乳动物精子表面。 顶体反应是一种胞吐反应， 涉及质膜与下面的顶体融合的事件 膜，随后释放顶体内容物。 它需要用于 受精 透明藻被认为是一种生理诱导物， 顶体反应，但控制胞吐作用的机制不是 很好理解。 Ca ~（2+）和Cl ~-通量是诱导细胞凋亡所必需的。 顶体反应。 P.I.的最新研究的 实验室表明GlyR/Cl-通道参与了透明带介导的 途径，尽管不确定是否存在这样的受体， 它在顶体反应中的作用是什么 这 应用测试了GlyR激活产生Cl-流出的假设 并且由此产生的去极化激活了电压敏感的Ca 2 + 渠道 私家侦探旨在描述精子GlyR的特征，并确定其在 顶体反应 研究将在人类和 猪系统 在目标1中，共聚焦显微镜将用于定位 BODIPY-士的宁，一种推定的GlyR探针，在活的和固定的人上 精子 目标2将使用以下方法监测人类精子中Gly依赖性Cl-通量： MEQ荧光探针。 某些GlyR激动剂，拮抗剂， 和人精子中Cl-和顶体反应的增强剂将是 测定 目的4将确定GlyR介导的Cl-流出是否 通过电压敏感性Ca 2+通道激活Ca 2+内流。 内部 将通过以下方法测定单个精子对Gly刺激的Ca 2+反应： 定量荧光显微镜，与Nuccitelli合作。 其他研究将确定Ca 2+通道拮抗剂对 这个回应。 目标5-7涉及生物化学和功能 猪GlyR的表征。 在Aim 5中，PI将溶解 猪精子膜，并通过亲和层析分离受体。 将对分离的受体进行生化表征。

DESCRIPTION (Adapted from the Investigator's Abstract): This revised proposal addresses examines the role of a putative glycine receptor (GlyR) on the mammalian sperm surface. The acrosome reaction is an exocytotic event involving fusion of the plasma membrane with the underlying acrosomal membrane, followed by release of acrosomal contents. It is required for fertilization. The zona pellucida is believed to be a physiological inducer of the acrosome reaction, but the mechanisms that control exocytosis are not well understood. Ca2+ and Cl- fluxes are required for the induction of the acrosome reaction by the zona pellucida. Recent studies from the P.I.'s laboratory indicate that a GlyR/Cl- channel is involved in the zona-mediated pathway, although it is not certain whether such a receptor is present and what the nature of its role in the acrosome reaction might be. This application tests the hypothesis that GlyR activation produces Cl- efflux and that the resulting depolarization activates voltage-sensitive Ca2+ channels. The P.I. intends to characterize a sperm GlyR and to determine its role in the acrosome reaction. Studies will be carried out in both the human and pig systems. In Aim 1 confocal microscopy will be used to localize BODIPY-strychnine, a probe for the putative GlyR, on live and on fixed human sperm. Aim 2 will monitor Gly-dependent Cl- fluxes in human sperm using the MEQ fluorescent probe. The effects of certain GlyR agonists, antagonists, and potentiators on Cl- and acrosome reactions in human sperm will be determined. Aim 4 will determine whether the GlyR-mediated Cl- efflux activates a Ca2+ influx through voltage-sensitive Ca2+ channels. Internal Ca2+ responses to Gly stimulation will be determined in single sperm by quantitative fluorescence microscopy, in collaboration with Nuccitelli. Additional studies will determine the effects of Ca2+ channel antagonists on this response. Aims 5-7 address the biochemical and functional characterization of the porcine GlyR. In Aim 5, the P.I. will solubilze boar sperm membranes and isolate the receptor by affinity chromatography. Biochemical characterization of the isolated receptor will be performed.