Ligand Directed Functional Selectivity of G-Protein Coupled Receptor Signalling

G 蛋白偶联受体信号转导的配体定向功能选择性

基本信息

批准号：
8113250
负责人：
GERRY S OXFORD
金额：
$ 31.62万
依托单位：
INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-08-01 至 2013-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8113250
关键词：
Adenylate Cyclase Adverse effects Affinity Agonist Arrestins Autoreceptors Behavior Binding Binding Proteins Brain Cell Line Cells Complement Complex Coupling DNA Sequence Rearrangement Data Development Disease Dissociation Dopamine Dopamine Agonists Dopamine D2 Receptor Dopamine Receptor Drug Delivery Systems Elements Endocrine System Diseases Enzymes Event Exposure to Family G Protein-Coupled Receptor Signaling G protein-coupled inwardly-rectifying potassium channel G-Protein-Coupled Receptors GTP-Binding Proteins Genes Guanine Nucleotides Heterotrimeric GTP-Binding Proteins Hormones Human Intracellular Membranes Ion Channel Ligands Light MAPK3 gene Membrane Proteins Mental disorders Midbrain structure Mitogen-Activated Protein Kinases Modeling Molecular Molecular Conformation Mus Mutation Nature Neurons Neurosecretory Systems Neurotransmitter Receptor Neurotransmitters Nucleus Accumbens Outcome P-Q type voltage-dependent calcium channel Pathway interactions Pattern Peptide Signal Sequences Pharmaceutical Preparations Pharmacologic Substance Pharmacology Pharmacotherapy Population Preparation Process Protein Isoforms Protein Subunits Proteins Publishing Quinpirole Rattus Receptor Activation Receptor Signaling Relative (related person)Research Resistance Role Schizophrenia Signal Pathway Signal Transduction Small Interfering RNA Specific qualifier value Specificity Stimulus Substance abuse problem Synapses System Technology Testing Theoretical Studies Tissues Transmembrane Domain arrestin 2 base desensitization dimer dopamine D3 receptor drug development functional outcomes intermolecular interaction member neuropsychiatry novel protein complex public health relevance receptor receptor coupling research study response stoichiometry theories therapy outcome trafficking

项目摘要

DESCRIPTION (provided by applicant): Transduction of many external stimuli (e.g. light, odorants, neurotransmitters, hormones) by cells in all tissues occurs through activation of members of a large gene superfamily called G-protein coupled receptors (GPCRs) that couple receptor activation to complex cascades of signaling events through a vast and expanding array of intracellular and membrane bound proteins. A common feature of the transduction process for GPCRs is the intermediation of heterotrimeric G-proteins. Upon agonist binding to GPCRs, dissociation or rearrangement of the cognate G1 and G23 subunits is thought to trigger stimulation or inhibition of various enzymes, ion channels, and other effector molecules. Classical receptor theory suggests that any agonist of a specific GPCR will induce the same conformational changes, and that differences in efficacy and potency among agonists reflect only the coupling efficiency (strength of signal) and relative binding affinity. Recent evidence for a number of GPCRs has alternatively suggested the existence of ligand-specific conformations that preferentially traffic receptor activation to select subsets of signaling pathways resulting in distinct signal cascades for different agonists through the same GPCR isoform. In the case of the human D2 dopamine receptor, we have discovered selective activation patterns (potency and intrinsic activity) for K and Ca channels, adenylyl cyclase, and MAP kinase upon exposure to the agonists quinpirole, DHX, and NPA. The underlying molecular mechanisms for this "functional selectivity" of agonist action are unknown. In the proposed research we will examine mechanisms underlying functional receptor-signal complexes in the neuroendocrine AtT20 cell line and primary rat neurons through four specific aims: (1) To define ligand- dependent selectivity of D2 and D3 dopamine receptors coupled to five effectors; adenylyl cyclase (AC), Kir3.0 channels, CaV2.0 channels, p42/44 MAP kinase (Erk1/2), and 2-arrestin translocation. (2) To assess the parameters of functional selectivity for native D2 receptor signaling in rat midbrain neurons. (3) To test the contribution of conserved residues in transmembrane domains (TM2, TM5, TM7) and intracellular loops previously shown to be signal switches in other GPCRs to functional selectivity of agonist signaling through D2 receptors. (4) To test the hypothesis that specific receptor/G1-protein complexes confer agonist-dependent functional selectivity. These experiments will increase understanding of the role of intermolecular interactions in specifying the potency and efficacy of dopaminergic ligands and, in turn, will have impact on the development of drugs targeted toward several neuropsychiatric and endocrine disorders. PUBLIC HEALTH RELEVANCE: This research explores the molecular basis for a novel signaling phenomenon, termed "functional selectivity", by which different drugs and neurotransmitters can direct very different signaling outcomes through the same isoform of neurotransmitter receptor. We will focus on an important class of dopamine receptors widely implicated in substance abuse behaviors as well as several psychiatric disorders such as schizophrenia. As the receptors are important targets for pharmaco-therapies, the outcome of our research will guide the development of more refined and specific drugs for these disorders with fewer side effects.

描述（由申请人提供）：所有组织中细胞中许多外部刺激（例如光，气味，神经递质，激素，激素）的转导，是通过激活大型基因超家族的成员，称为G蛋白偶联受体（GPCR）的成员，通过将受体激活与广泛的范围内的范围扩展和扩展的范围内的范围内的数组相结合，使得受体激活，并将其逐渐扩展到范围内。 GPCR的转导过程的一个共同特征是异三聚体G蛋白的中介。在激动剂与GPCR结合时，人们认为同源G1和G23亚基的解离或重排被触发刺激或抑制各种酶，离子通道和其他效应分子。经典受体理论表明，特定GPCR的任何激动剂都会引起相同的构象变化，并且激动剂之间的疗效和效能的差异仅反映了耦合效率（信号强度）和相对结合亲和力。许多GPCRS的最新证据替代表明，配体特异性构象的存在优先通过相同的GPCR同工型来选择信号传导途径的子集以选择信号传导途径的亚集，从而为不同的激动剂提供了独特的信号级联。对于人类D2多巴胺受体，我们发现了K和Ca通道，腺苷酸环化酶和MAP激酶的选择性激活模式（效力和内在活性），并在暴露于激动剂奎因螺螺旋，DHX和NPA时进行了MAP激酶。这种激动剂作用的“功能选择性”的基本分子机制尚不清楚。在拟议的研究中，我们将通过四个特定目的研究神经内分泌ATT20细胞系和原代大鼠神经元中功能受体信号复合物的机制：（1）定义与五个效应子相关的D2和D3多巴胺受体的配体依赖性选择性；腺苷酸环化酶（AC），KIR3.0通道，CAV2.0通道，P42/44 MAP激酶（ERK1/2）和2- arrestin易位。（2）评估大鼠中脑神经元中天然D2受体信号传导功能选择性的参数。（3）测试跨膜结构域（TM2，TM5，TM7）和细胞内环中保守残基的贡献先前证明是其他GPCR中的信号开关对通过D2受体的激动剂信号传导的功能选择性。（4）检验了特定受体/G1蛋白复合物赋予激动剂依赖性功能选择性的假设。这些实验将增加对分子间相互作用在指定多巴胺能配体的效力和功效中的作用的理解，进而将影响针对几种神经精神疾病和内分泌疾病的药物的发展。公共卫生相关性：这项研究探讨了一种新型信号传导现象的分子基础，称为“功能选择性”，通过该现象，不同的药物和神经递质可以通过神经递质受体的相同同工型引导非常不同的信号传导结果。我们将重点关注一类重要的多巴胺受体，广泛涉及滥用药物的行为以及几种精神分裂症等精神疾病。由于受体是药物治疗的重要靶标，因此我们研究的结果将指导为这些疾病的更精致和特定的药物的开发，而这些疾病的副作用较少。