SIGNAL TRANSDUCTION OF THE D2 DOPAMINE RECEPTOR SUBTYPES

描述：（改编自申请人的摘要） 研究建议是阐明两种亚型的信号传导， D2多巴胺受体。 这些受体是选择性剪接形式的 相同的基因，其在蛋白质水平上通过添加29个氨基酸而不同 酸在第三个细胞质环，产生长和短的形式。 的 两种同种型在所有组织中共表达，尽管比例不同。 先前的工作表明，这两种受体与不同的Gi偶联， 调节细胞效应物的蛋白质，如腺苷酸环化酶。 这 该提案将集中于阐明每个亚型的区域， 负责其与G蛋白的特异性相互作用。 的方法 提出的是在同种型和表达中产生点突变， 这些突变体在GI特异性背景下的功能性评估。 使用 这种方法将允许定义氨基酸， 受体-G蛋白相互作用的特异性。 最终，目标是 阐明这些亚型的哪些氨基酸残基负责 受体-G蛋白界面的特异性。 的具体目标 该建议是：1）在D2中产生相同的点突变， 2）在Gi特异性背景中表达突变体受体3）评估 突变对腺苷酸环化酶信号传导的影响4）评估效应 与G蛋白的物理相互作用。 D2多巴胺 受体与几种疾病有关，如帕金森病和 精神分裂症;了解管理特异性的机制 D2多巴胺受体的信号传导可能具有重要的意义， 被认为是多巴胺能功能障碍引起的疾病。

DESCRIPTION: (adapted from the applicant's abstract) The goal of this research proposal is to elucidate the signaling of the two isoforms of the D2 dopamine receptor. These receptors are alternative splice forms of the same gene, which differ at the protein level by the addition of 29 amino acids in the third cytoplasmic loop, generating a long and short form. The two isoforms are co-expressed in all tissues, albeit in varying ratios. Previous work has shown that these two receptors couple to distinct Gi proteins to regulate cellular effectors, such as adenylyl cyclase. This proposal will focus on elucidating the regions of each isoform which are responsible for its specific interaction with G proteins. The approach proposed is the creation of point mutations in both isoforms and expression of these mutants in a Gi-specific background to assess functionality. Using this approach will allow the definition of amino acids which dictate the specificity of receptor-G protein interaction. Ultimately, the goal is to elucidate which amino acids residues of these isoforms are responsible for the specificity at the receptor-G protein interface. The specific aims of this proposal are to: 1) create identical point mutations in both D2s and D2l 2) express the mutant receptors in a Gi specific background 3) assess the effect of mutation on signaling to adenylyl cyclase 4) assess the effect of mutation on the physical interaction with G proteins. The D2 dopamine receptors are implicated in several diseases, such as Parkinson's and schizophrenia; understanding the mechanisms that govern the specificity of the signaling of the D2 dopamine receptors may have important implications in disorders thought to result from dopaminergic dysfunction.