MEMBRANE EVENTS FOLLOWING HORMONE BINDING TO LH RECEPTOR

在人类中，促黄体生成激素（LH）和人绒毛膜 促性腺激素（hCG）调节孕酮的分泌， 黄体在月经周期和早期 怀孕 这一建议将加强对这些问题的了解， 促性腺激素调节黄体细胞功能， 了解激素相关的物理事件 与细胞表面受体和其他膜的相互作用 件. 人和绵羊黄体细胞的相似性 使母羊成为研究物理的优良模型系统 伴随hCG或LH与LH受体结合的事件。 的 结合亲和力、内化速率和细胞对 短期和长期的激素暴露的特点是 hCG和LH对绵羊黄体细胞的影响。 这项提案的目的是 检测LH受体聚集、分布和分子水平， 绵羊发情期黄体细胞的运动 周期，并探讨如何物理行为的LH受体 受其与oLH或hCG相互作用的影响。 第一，程度 将在活细胞上测量LH受体聚集 在激素结合之前和之后使用荧光能量 LH受体旋转运动的转移和测量。 受体分布将使用计算机增强的 低光显微镜和电子显微镜。 二、作用 hCG和oLH的α和β亚基以及 与这些分子相关的碳水化合物 LH受体的侧向和旋转运动 将被确定。 异源二聚体形成的影响， hCG和oLH亚基及去糖基化hCG对分布 检查LH受体的运动。 三是我们 初步研究表明，hCG-LH受体侧 运动受到细胞骨架成分的限制。 我们将 表征细胞骨架与LH受体的相互作用 在激素结合前后。 最后，我们将尝试 确定其他黄体细胞膜蛋白是否 与黄体生成素受体相互作用。 等 相互作用可能会显著限制 LH受体。 科罗拉多州立大学有一个不同寻常的 生殖生理学专业知识和 研究膜蛋白动力学的仪器设备。 这种情况为我们提供了一个独特的机会， 关于发生的膜事件的详细信息 在激素与LH受体结合后。

In humans, luteinizing hormone (LH) and human chorionic gonadotropin (hCG) regulate the secretion of progesterone from the corpus luteum during the menstrual cycle and early pregnancy. This proposal will enhance understanding of how these gonadotrophs regulate luteal cell function by adding to our knowledge of the physical events surrounding hormone interactions with cell surface receptors and other membrane components. Similarities between human and sheep luteal cells make the ewe an excellent model system for studying physical events accompanying hCG or LH binding to the LH receptor. The binding affinity, rate of internalization, and cellular response to brief and prolonged hormone exposure have been characterized for hCG and LH on ovine luteal cells. The goal of this proposal is to examine LH receptor aggregation, distribution, and molecular motions on ovine luteal cells during the luteal phase of the estrous cycle and to explore how the physical behavior of the LH receptor is affected by its interactions with oLH or hCG. First, the extent of LH receptor aggregation will be measured on viable cells before and after hormone binding using fluorescence energy transfer and measurements of LH receptor rotational motions. Receptor distribution will be examined using computer-enhanced low light microscopy and electron microscopy. Second, the role of the alpha and beta subunits of hCG and oLH and the carbohydrates associated with these molecules in modifying lateral and rotational motions of hormone-occupied LH receptors will be determined. The effects of heterodimers formed from hCG and oLH subunits and deglycosylated hCG on the distribution and motion of LH receptor will be examined. Third, our preliminary studies indicate that hCG-LH receptor lateral motions are constrained by cytoskeletal components. We will characterize cytoskeletal interactions with the LH receptor before and after hormone binding. Finally, we will attempt to determine whether other luteal cell membrane proteins are interacting with the hormone-occupied LH receptor. Such interactions may significantly restrict the lateral movement of the LH receptor. Colorado State University has an unusual confluence of expertise in reproductive physiology and of instrumental facilities for studies of membrane protein dynamics. This situation affords us a unique opportunity to obtain new and detailed information regarding membrane events which occur following hormone binding to the LH receptor.