LH Receptor C-terminus in Receptor Desensitization

描述（由申请人提供）：促黄体生成的脱敏 激素（LH）受体，即出现无反应状态 在卵母细胞减数分裂过程中， 在LH峰后和受体内化在其他时间， 卵巢周期 短暂暴露于LH或人绒毛膜促性腺激素 (hCG)导致LH受体脱敏和LH受体聚集， 大的显微镜可见的结构。 受体保持对 直到这些可见的结构 消散 申请人假设大鼠LH的C末端 受体含有对受体脱敏至关重要的信息， 用于将LH受体靶向至特定质膜微区。 到 评估LH受体C末端的作用，申请人将使用 衍生自“抗脱敏”促性腺激素的嵌合受体 促性腺激素释放激素（GnRH）受体，其缺乏细胞内C末端， 其不表现出脱敏。 申请人将这些受体 LH受体C-末端（GnRH/cLH受体），并确定是否 该结构域的加入赋予GnRH受体脱敏能力。 在具体目标1中，申请人将确定这些嵌合体是否 受体表现出过敏诱导的脱敏，如果是这样，多久， 状态和相关受体的自我关联持续存在。 在具体目标2中， 申请方将评估是否存在促性腺激素治疗的GnRH/cLH受体， 大的，可见的簇复合物，如脱敏的LH受体，或者，如果不是， 无论它们形成孤立的二聚体还是小的寡聚体。 具体目标3中， 申请人将使用单粒子跟踪来确定是否脱敏 GnRH/cLH和野生型LH受体都占据类似大小的膜结构域 以及这些畴大小是否在重新敏化时改变。 这些研究 将借鉴主要研究者的经验以及 科林·克莱博士的专业知识，动物繁殖和 生物技术实验室，以及乔治巴里萨斯博士，一个生物制药学家， 科罗拉多州立大学。 尽管她将开发和利用几个国家的- 艺术生物物理方法来研究G蛋白受体功能，该项目 尽管如此，它的范围有限，很可能在2010年内完成。 两年

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.