Structure and function of dopamine receptors

描述(申请人提供)：儿茶酚胺多巴胺在认知、情绪和行为功能的调节中起主要作用，其调节的异常与许多精神和神经疾病有关。多巴胺通过D2样受体(D2、D3、D4)和D1样受体(D1D5)发挥作用，它们是七个跨膜段G蛋白偶联受体(GPCR超家族)的成员。该项目的长期目标是：1)了解激动剂和拮抗剂结合的结构基础以及多巴胺受体和相关生物胺受体的特异性；2)确定激动剂结合是如何转化为G蛋白激活的。许多用于治疗精神疾病的药物，包括精神分裂症、注意力缺陷多动障碍(ADHD)和抑郁症，直接或间接地针对多巴胺受体。我们提出了以下具体目标：1.确定具有代表性的A家族GPCR多巴胺D2受体(D2R)信号单元的功能化学计量学。我们将确定两个受体是否通过单一的异三聚体G蛋白传递信号，激活D2R的单个信号单位所需的激动剂的数量，以及激动剂或拮抗剂结合第二原始体在同体和异体信号单位中的作用。2.用生化、生物物理和光学方法研究D2R异二聚化在原代培养和体内黑腹果蝇神经元中的特异性。3.利用一种新型的基于共振能量转移的G蛋白激活生物传感器来区分D2R异构体和D2R在信号传递中的作用。为了完成我们的目标，我们将结合实验、结构和计算方法来研究受体的结构和功能。除了异种细胞的研究外，我们还将使用小鼠伏隔核培养液中的刺神经元和黑腹果蝇作为模型系统，进一步剖析同种和异种受体信号在体内的重要性。此外，我们将使用我们最新开发的基于能量转移的生物传感器来实时将异构体受体复合体与G蛋白激活联系起来。7.与公众健康的相关性：许多用于治疗精神疾病的药物，包括精神分裂症、注意力缺陷多动障碍(ADHD)和抑郁症，直接或间接地针对多巴胺受体。多巴胺受体可能存在于同构体和异构体与其他GPCR的复合体中并发挥作用，这开启了新的药理学可能性，如果基于对这种信号串扰的机制基础的清楚理解，这种可能性将得到最好的利用。

DESCRIPTION (provided by applicant): The catecholamine dopamine plays a major role in the regulation of cognitive, emotional and behavioral functions, and abnormalities in its regulation have been implicated in a number of psychiatric and neurological disorders. Dopamine acts through D2-like (D2, D3, D4) and D1-like (D1, D5) receptors, which are members of the seven transmembrane segment G protein-coupled receptor (GPCR) superfamily. The long-term goals of this project are: 1) to understand the structural bases of agonist and antagonist binding and specificity in dopamine receptors and related biogenic amine receptors and 2) to determine how agonist binding is transduced into G protein activation. Many drugs used to treat psychiatric disorders, including schizophrenia, attention-deficit hyperactivity disorder (ADHD), and depression, target dopamine receptors, either directly or indirectly. We propose the following specific aims: 1. To determine the functional stoichiometry of the signaling unit of the dopamine D2 receptor (D2R), a representative Family A GPCR. We will determine whether two receptors signal through a single heterotrimeric G protein, the number of agonists required to activate a single signaling unit of D2R, and the role of agonist or antagonist binding to the second protomer in homomeric and heteromeric signaling units. 2. To determine the specificity of D2R heterodimerization in neurons in primary culture and in vivo in Drosophila melanogaster using biochemical, biophysical, and optical methods. 3. To differentiate the role of signaling of D2R homomers and heteromers using a novel resonance energy transfer based-biosensor for G protein activation. To complete our objectives we will combine experimental, structural, and computational approaches to receptor structure and function. In addition to work in heterologous cells, we will use mouse nucleus accumbens medium spiny neurons in primary culture and Drosophila melanogaster as a model system to dissect further the importance of homo- and heteromeric receptor signaling in vivo. Moreover, we will use our newly developed energy transfer based-biosensor to link biophysically the heteromeric receptor complex with G protein activation in real time. 7. PUBLICE HEALTH RELEVANCE: Many drugs used to treat psychiatric disorders, including schizophrenia, attention-deficit hyperactivity disorder (ADHD), and depression, target dopamine receptors, either directly or indirectly. That dopamine receptors may exist and function in homo- and heteromeric complexes with other GPCRs opens new pharmacological possibilities that will be best exploited if based on a clear understanding of the mechanistic basis of this signaling crosstalk.