REGULATION OF THE PTH/PTHRP RECEPTOR

PTH/PTHRP 受体的调节

• 批准号: 6564095
• 负责人: ABDUL B ABOU-SAMRA
• 金额: $ 14.33万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-12-01 至 2002-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6564095
• 关键词: G protein; antireceptor antibody; biological signal transduction; cell line; fluorescence microscopy; green fluorescent proteins; hormone receptor; hormone regulation /control mechanism; osteoblasts; parathyroid hormone related protein; parathyroid hormones; phosphorylation; protein kinase; receptor binding; receptor sensitivity; transfection

Description:(Taken directly from the application) The diverse endocrine actions of PTH and paracrine actions of PTHrP are determined by the local concentrations of ligands and the responsiveness of target cells. Cellular responsiveness is determined by the number of receptors at the cell surface, the ability of receptors to convert ligand binding to G protein(s) activation, and the distal biological responses to G protein(s). This proposal will focus on understanding the post-translational events that regulate the responsiveness of the PTH/PTHrP receptor. We have powerful tools for probing the molecular mechanisms involved in each of these processes. These include specific receptor antibodies, green-fluorescent protein-tagged receptors, and libraries of mutant receptors (phosphorylation-deficient, constitutively-active, activation-deficient and Gq-deficient), PTH analogs (AC-selective) and stable bone-derived cell lines with different patterns of differentiation and activation of bone-specific genes in response to continuous versus intermittent PTH treatment. In Aim I the phosphorylation sites will be mapped and the role of receptor phosphorylation and of G protein receptor kineses in internalization and desensitization will be determined. In Aim II, mutant receptors, which dissociate binding from activation, will be used to determine if binding and/or activation is/are required for phosphorylation, internalization and/or desensitization. In Aim III the green fluorescent protein-tagged PTH/PTHrP receptors will be used to characterize the cellular proteins that associate with the internalized PTH/PTHrP receptor vesicles and to examine the role of receptor phosphorylation in this process. The physiological relevance of internalization and desensitization will be examined in the bone-derived cell lines that have different patterns of biologic responses to continuous versus intermittent PTH treatment. We propose in Aim IV to interfere with the desensitization process in these cells and determine how this interference affects the osteoblast's responses to intermittent versus continuous administration of PTH.

描述：（直接从应用中取出）PTHRP的PTH和旁分泌作用的多种内分泌作用取决于配体的局部浓度和靶细胞的响应性。细胞反应能力取决于细胞表面的受体数量，受体转化配体结合G蛋白激活的能力以及对G蛋白的远端生物学反应。该建议将集中于理解调节PTH/PTHRP受体反应性的翻译后事件。我们有强大的工具来探测每个过程中涉及的分子机制。这些包括特定的受体抗体，绿色荧光蛋白标记的受体以及突变受体的文库（缺乏磷酸化，活性，激活缺陷和GQ缺乏症），PTH类似物（AC-SELECECTION）（AC-SELECTICTY）以及稳定的骨源性细胞的分化和激活构成的骨骼分化的细胞，并具有稳定的骨骼细胞，使骨的分化量构成构成构成的分化。 治疗。在目标I中，将映射磷酸化位点，并将确定受体磷酸化和G蛋白受体酮在内在化和脱敏化中的作用。在AIM II中，将分解与激活结合的突变受体将用于确定磷酸化，内在化和/或脱敏是否需要结合和/或激活。在AIM III中，将使用绿色荧光蛋白标记的PTH/PTHRP受体来表征与内部PTH/PTHRP受体囊泡相关的细胞蛋白，并检查受体磷酸化在此过程中的作用。内部化和脱敏的生理相关性将在骨衍生的细胞系中进行检查，这些细胞系具有不同对连续和间歇性PTH处理的生物学反应模式。我们建议在AIM IV中干扰这些细胞中的脱敏过程，并确定这种干扰如何影响成骨细胞对间歇性与持续施用PTH的反应。