NEUROENDOCRINE CGRP RECEPTORS

我们最近发现了一种新的低分子量蛋白质，它 似乎是受体信号转导所必需的 降钙素基因相关肽(CGRP)，并可能存在于其他G 蛋白质偶联受体。这种小的亲水性蛋白质具有 被命名为CGRP所需的受体成分蛋白(RCP)。 NIH3T3细胞中介导的信号转导。我们已经演示了 稳定的NIH3T3对RCP在CGRP受体功能中的要求 表达RCP反义c DNA的细胞株，并观察到丢失 伴随着CGRP受体活性的丧失的RCP蛋白。RCP 是在CGRP受体的背景下发现的，但它的作用可能 不限于CGRP受体。为了努力了解更多关于 这种新的蛋白质的功能我们已经集中在我们的初步研究 降钙素基因相关肽受体的激活。我们不认为RCP代表 受体本身，就像RCP转染COS成纤维细胞一样 不能产生功能性的CGRP受体。相反，我们假设RCP 与一种跨膜的配体结合蛋白协同工作 形成一个有功能的CGRP受体。两个CGRP受体最近 已被鉴定，但将RCP与其中任何一种共转染 进入COS成纤维细胞的受体不能重组CGRP受体 功能，暗示一种新的受体与RCP一起工作 在NIH3T3细胞中。 我们的假设是，RCP作用于受体靶向 细胞表面，或受体与信号转导的偶联 分子。这项提案中概述的实验结果 将在这两种可能性之间辨别。这样做的具体目的是 建议：1)确定NIH3T3细胞中RCP的丢失 抑制降钙素基因相关肽以外的受体。2)确定RCP在 受体分选或受体偶联。3)确定受体(S) 需要RCP才能发挥作用的NIH3T3细胞。我们使用的是CGRP NIH3T3细胞中存在的受体作为RCP依赖受体的模型 探讨RCP的作用机制。CGRP是最多的 已知有效的血管扩张剂，降钙素基因相关肽结合部位广泛分布 遍及整个心血管系统。蛋白质的特性研究 参与CGRP受体激活对CGRP的发育具有重要意义 受体模型系统，这将促进治疗的发展 用于治疗高血压等心血管疾病的配体。

We have recently discovered a novel low molecular weight protein which appears to be required for signal transduction at receptors for calcitonin gene-related peptide (CGRP), and potentially at other G protein-coupled receptors. This small hydrophilic protein which has been named the Receptor Component Protein (RCP) is required for CGRP- mediated signal transduction in NIH3T3 cells. We have demonstrated the requirement for RCP in CGRP receptor function by making stable NIH3T3 cell lines which express RCP antisense cDNA, and have observed a loss of RCP protein with a concomitant loss of CGRP receptor activity. RCP was discovered in the context of the CGRP receptor, but its effects may not be limited to receptors for CGRP. In an effort to learn more about the function of this novel protein we have focused our initial studies on CGRP receptor activation. We do not believe that RCP represents a receptor itself, as transfection of RCP into COS fibroblast cells does not yield functional CGRP receptors. We instead hypothesize that RCP works in conjunction with a membrane-spanning, ligand-binding protein to form a functional CGRP receptor. Two CGRP receptors have recently been identified, but cotransfection of RCP with either of these receptors into COS fibroblasts fails to reconstitute CGRP receptor function, implicating a novel receptor working in conjunction with RCP in NIH3T3 cells. Our hypothesis is that RCP effects either targeting of receptor to the cell surface, or coupling of the receptor to signal transduction molecules. The results from the experiments outlined in this proposal will discern between these two possibilities. The Specific Aims of this proposal are to: 1) Determine if the loss of RCP in NIH3T3 cells inhibits receptors other than CGRP. 2) Determine if RCP functions in receptor sorting or receptor coupling. 3) Identify the receptor(s) in NIH3T3 cells that require RCP for function. We are using the CGRP receptor present in NIH3T3 cells as a model for RCP-dependent receptors to determine the mechanism of RCP function. CGRP is one of the most potent vasodilators known, and CGRP binding sites are distributed widely throughout the cardiovascular system. Characterization of the proteins involved in CGRP receptor activation is important for developing CGRP receptor model systems, which will facilitate development of therapeutic ligands for treatment of cardiovascular disease such as hypertension.