FUNCTION OF CALCITONIN RECEPTORS

降钙素受体的功能

• 批准号: 6100313
• 负责人: STEVEN GOLDRING
• 金额: --
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-01-01 至 1998-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6100313
• 关键词: G protein; arthritis; autoradiography; calcitonin; hormone receptor; immunocytochemistry; in situ hybridization; laboratory mouse; laboratory rat; molecular cloning; northern blottings; organ culture; pathologic bone resorption; phosphorylation; protein isoforms; protein structure function; radioimmunoassay; receptor binding; receptor coupling; receptor expression; site directed mutagenesis

The recent cloning of porcine, human and murine calcitonin receptors (CTRs) by our laboratory and analysis of their structural features indicates that they belong to a new family of G protein-coupled receptors that includes the receptors for several members of the secretin/glucagon peptide family and parathyroid hormone/parathyroid hormone related peptide. The CTR cDNAs have provided us with experimental tools to define the molecular basis for the broad spectrum of biological and pharmacological effects of calcitonin (CT) and for determining the mechanisms underlying the observed cross-reactivity of CT with related ligands. The basis for the unique functional properties of the CTR, including the capacity to couple to multiple signal transduction pathways and to produce sustained activation of adenylate cyclase can also be explored. Initial studies indicate the presence of CTR isoforms and possibly subtypes with distinct functional properties. These findings provide the basis for Specific Aim 1 which is to clone and characterize the structural and functional properties of different CTR isoforms and related receptors. The observed structural and functional heterogeneity that we have detected among the CTR cDNAs that we have already cloned could proved the basis for tissue-specific regulation of responses to CT and related peptides. Specific Aim 2 will use in situ hybridization with probes prepared from the CTR clones and immunohistochemistry with antibodies to the CTR, to establish the tissue distribution of these receptors. Because the CTR family of receptors exhibits structural features that are different from the other members of the G protein- coupled receptor super family, the structure/function relationships for these additional clone CTR cDNAs, to define the structural determinants underlying the unique functional properties of the CTR. Specific Aim 3 proposes to use techniques of site-directed mutagenesis and construction of chimeric receptors to define the structural domains associated with ligand binding and coupling to G proteins associated with activation of specific signaling pathways. The development of refractoriness ("escape") to the hypocalcemic effects of CT is a significant problem in the clinical and therapeutic use of CT. Insights into the mechanisms underlying this condition should lead to more effective use of CT in the treatment of disorders of skeletal remodeling. The goal of Specific Aim 4 will be to define the molecular and cellular basis of this state of refractoriness to CT and to establish its relationship to the processes of receptor desensitization and down-regulation.

猪，人和鼠降钙素受体的最近克隆 （CTRS）通过我们的实验室和对结构特征的分析 表示它们属于G蛋白偶联受体的新家族 其中包括秘密蛋白/胰高血糖素的几个成员的受体 肽家族和甲状旁腺激素/甲状旁腺激素相关 肽。 CTR CDNA为我们提供了实验工具 定义广泛生物学和的分子基础 降钙素（CT）的药理作用，并确定 与相关的CT观察到的交叉反应性的机制 配体。 CTR的唯一功能特性的基础 包括夫妇到多个信号转导途径的能力 并产生腺苷酸环化酶的持续激活也可以是 探索。 初步研究表明存在CTR同工型和 可能具有不同功能特性的亚型。 这些发现 为特定目标1提供基础，即克隆和表征 不同CTR同工型的结构和功能特性以及 相关受体。 观察到的结构和功能异质性 我们已经在CTR CDNA中检测到已经克隆的 可以证明组织特异性调节CT的反应的基础 和相关的肽。 特定的目标2将与原位杂交与 由CTR克隆制备的探针和免疫组织化学 CTR的抗体，以建立这些组织分布 受体。 因为CTR的受体家族表现出结构性 与G蛋白的其他成员不同的特征 耦合受体超级家族，结构/功能关系 这些额外的克隆CTR cDNA，以定义结构决定因素 CTR的独特功能特性的基础。 具体目标3 建议使用定向诱变和构造技术 嵌合受体的定义与 配体结合和与与激活相关的G蛋白的偶联 特定的信号通路。 磨性的发展 （“逃脱”）CT的降钙症作用是一个重要的问题 CT的临床和治疗用途。 洞悉机制 这种条件的基础应导致更有效地使用CT 治疗骨骼重塑的疾病。 特定目标的目标 4将定义该状态的分子和细胞基础 对CT的折磨性并建立与过程的关系 受体脱敏和下调。