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。 国集团 蛋白偶联受体，这一过程是复杂的， Gi亚型。 该提案将侧重于1）建设和 在第一和第二位点处含有取代的Gi蛋白的表征 百日咳毒素修饰位点，这将使它们对 百日咳毒素2）产生含有单一形式的 功能性G蛋白3）G蛋白和效应物偶联的比较 大鼠纹状体D2多巴胺受体的两种剪接形式。 这些 方法将有助于确定调控受体的机制， 信号传递到效应器系统。 到目前为止，人们对它知之甚少。 允许高保真跨膜信号的机制 响应于受体活化的转导。 使用分子生物学 技术，含有百日咳毒素位点突变的G蛋白 最终将被导入永久性I型克隆细胞系， 百日咳毒素中毒后，将只含有突变体G 蛋白质的功能形式。 这种方法将使受体 介导的效应子应答，以在存在单一 定义的Gi亚型。 这些综合办法将有助于澄清 信号转导的生化基础。 由于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， 它的信号机制可能对一些 在被认为以多巴胺能功能障碍为基础的疾病中， 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.