NEUROENDOCRINE CGRP RECEPTORS

我们最近发现了一种新的低分子量蛋白质， 似乎需要在受体的信号转导， 降钙素基因相关肽（CGRP），并可能在其他G 蛋白偶联受体 这种小的亲水性蛋白质 被命名为受体组分蛋白（RCP）是CGRP所必需的- 介导的信号转导。 我们已经展示了 通过使稳定的NIH 3 T3在CGRP受体功能中需要RCP 表达RCP反义cDNA的细胞系，并观察到 伴随着CGRP受体活性的丧失。 RCP 是在CGRP受体的背景下发现的，但它的作用可能 不限于CGRP的受体。 为了更好地了解 这种新蛋白的功能，我们集中我们的初步研究 对CGRP受体激活的影响 我们不认为RCP代表了 受体本身，因为RCP转染到COS成纤维细胞中， 不产生功能性CGRP受体。 相反，我们假设RCP 与跨膜配体结合蛋白协同作用 形成一个有功能的CGRP受体 最近，两种CGRP受体 但RCP与这些基因中的任何一种共转染 受体进入COS成纤维细胞不能重建CGRP受体 功能，暗示一种新的受体与RCP一起工作 在NIH 3 T3细胞中。 我们的假设是RCP影响受体靶向 细胞表面，或受体与信号转导的偶联 分子。 本提案中概述的实验结果 会分辨出这两种可能性 具体目标是 建议：1）确定NIH 3 T3细胞中RCP的丢失是否 抑制CGRP以外的受体。 2)确定RCP是否在 受体分选或受体偶联。 3)识别受体， NIH 3 T3细胞需要RCP才能发挥功能。 我们使用CGRP 作为RCP依赖性受体模型的NIH 3 T3细胞中存在的受体 以确定RCP功能的机制。降钙素基因相关肽是一种 已知有效的血管扩张剂，CGRP结合位点分布广泛 整个心血管系统。 蛋白质的表征 参与CGRP受体活化对于产生CGRP是重要的 受体模型系统，这将有助于开发治疗 用于治疗心血管疾病如高血压的配体。

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.