SIGNAL TRANSDUCTION OF THE D2 DOPAMINE RECEPTOR SUBTYPES

这项研究计划的目标是阐明 维持跨膜信号转导的保真度。对于G 蛋白偶联受体，这一过程因其多样性而变得复杂 胃肠道亚型。该提案将侧重于1)建设和 GI蛋白的特性研究 百日咳毒素修饰部位，使它们对 百日咳毒素2)产生含有单一形式的 功能G蛋白3)G蛋白与效应器偶联的比较 大鼠纹状体D2多巴胺受体的两种剪接形式。这些 方法将有助于确定控制受体的机制 向效应器系统发送信号。到目前为止，人们对此知之甚少 允许跨膜信号高保真的机制 受体激活后的信号转导。使用分子生物学 技术，百日咳毒素部位含有突变的G蛋白 最终将被导入永久的I克隆细胞系，该细胞系 百日咳毒素中毒后，只会含有突变的G 功能形式的蛋白质。这种方法将允许受体 介导性效应器反应在单一的 已定义GI子类型。这些组合方法将有助于澄清 信号转导的生化基础。因为多巴胺是一种重要的 外周的激素和中枢神经系统的神经递质，理解 它的信号机制可能会对一些 在被认为是以多巴胺能障碍为基础的疾病中， 比如精神分裂症和帕金森氏症。

The goal of this research proposal is to elucidate mechanisms which maintain the fidelity of transmembrane signal transduction. For the G protein coupled receptors, this process is made complex by the multiplicity of Gi subtypes. This proposal will focus on 1) construction and characterization of the Gi proteins which contain a substitution at the pertussis toxin modification site which will render them insensitive to pertussis toxin 2) creation of a cell which contains a single form of functional G protein 3) comparison of the G protein and effector coupling of the two splice forms of the rat striatal D2 dopamine receptor. These approaches will help to determine mechanisms which govern receptor signalling to effector systems. To date, little is known about the mechanisms which allow the high fidelity of transmembrane signal transduction in response to receptor activation. Using molecular biology techniques, G proteins which contain a mutation a the pertussis toxin site will ultimately be introduced into a permanent I clonal cell line, which after intoxication with pertussis toxin, will contain only the mutant G protein in a functional form. This approach will allow the receptor mediated effector responses to be examined in the presence of a single defined Gi subtype. These combined approaches will help to clarify the biochemical basis of signal transduction. Since dopamine is an important hormone in the periphery and a neurotransmitter in the CNS, understanding of its mechanisms of signalling could have important implications in some of the disorders thought to have a basis in i dopaminergic dysfunction, such as schizophrenia and Parkinson's disease.