LH Receptor C-terminus in Receptor Desensitization

描述(申请人提供)：黄体素脱敏 激素(LH)受体，即激素不反应状态的出现 在激素诱导信号传递之后，是完成卵母细胞减数分裂所必需的 在黄体生成素激增后和在其他时间的受体内化 卵巢周期。短期暴露于促黄体生成素或人绒毛膜促性腺激素 (HCG)引起黄体生成素受体失敏和聚集。 显微镜下可见的大型结构。受体仍然不敏感 荷尔蒙触发的信号直到这些可见的结构 消散。申请人假设大鼠黄体生成素的C-末端 受体包含对受体脱敏至关重要的信息，并且 用于将促黄体生成素受体靶向于特定的质膜微区。至 评估黄体生成素受体C末端的作用，申请人将使用 “脱敏抗性”促性腺激素来源的嵌合受体 释放激素(GnRH)受体，缺乏细胞内C末端和 没有表现出脱敏作用。申请者将把这些受体连接起来 与促黄体生成素受体C末端(GnRH/CLH受体)结合，并确定是否 这个结构域的加入使GnRH受体具有脱敏能力。 在具体目标1中，申请人将确定这些嵌合体是否 受体表现出激素诱导的脱敏作用，如果是的话，这种脱敏作用持续多久 状态和相关受体的自关联持续存在。在具体目标2中， 申请者将评估激素治疗的GnRH/CLH受体是否形成 大的、可见的簇状复合体，如脱敏的促黄体生成素受体，如果不是， 无论它们是形成孤立的二聚体还是形成小的低聚物。在具体目标3中， 申请者将使用单粒子跟踪来确定是否脱敏 GnRH/CLH和野生型黄体生成素受体都占据相似大小的膜结构域 以及这些结构域大小是否在重新增敏后发生变化。这些研究 将借鉴首席调查员的经验以及 科林·克莱博士的专业知识，他是动物繁殖部和 生物技术实验室，以及乔治·巴里萨斯博士，他是 科罗拉多州立大学。尽管她将开发和利用几个最先进的 ART生物物理方法研究G蛋白受体功能，本项目 尽管如此，范围还是有限的，很可能在 两年了。

DESCRIPTION (provided by applicant): The desensitization of luteinizing hormone (LH) receptors, namely the appearance of a hormone-unresponsive state after hormone-induced signaling, is essential for completion of oocyte meiosis following the LH surge and for receptor internalization at other times in the ovarian cycle. Brief exposure to either LH or human chorionic gonadotropin (hCG) causes LH receptor desensitization and clustering of LH receptors in large, microscopically-visible structures. Receptors remain desensitized to hormone-triggered signaling until such time as these visible structures dissipate. The applicant hypothesizes that the C-terminus of the rat LH receptor contains information critical for desensitization of the receptor and for targeting of LH receptors to specific plasma membrane microdomains. To evaluate the role of the LH receptor C- terminus, the applicant will use chimeric receptors derived from "desensitization-resistant" gonadotropin releasing hormone (GnRH) receptors, which lack an intracellular C-terminus and which do not exhibit desensitization. The applicant will link these receptors to the LH receptor C-terminus (GnRH/cLH receptors) and determine whether the addition of this domain confers desensitization capacity on the GnRH receptor. In Specific Aim 1, the applicant will determine whether these chimeric receptors exhibit hormone-induced desensitization and, if so, how long this state, and related receptor self-association, persists. In Specific Aim 2, the applicant will assess whether hormone-treated GnRH/cLH receptors form large, visible clusters complexes like desensitized LH receptors or, if not, whether they form isolated dimers or small oligomers. In Specific Aim 3, the applicant will use single-particle tracking to determine whether desensitized GnRH/cLH and wild type LH receptors both occupy similar-sized membrane domains and whether these domain sizes change upon resensitization. These studies will draw on the experience of the Principal Investigator as well as the expertise of Dr. Colin Clay, a member of the Animal Reproduction and Biotechnology Laboratory, and of Dr. George Barisas, a biophysicist at Colorado State University. Although she will develop and utilize several state-of-the- art biophysical approaches to study G-protein receptor function, this project is, nonetheless, of somewhat limited scope and likely to be completed within two years.