Structural Determinants of Kappa Opioid Receptor Signaling

项目摘要/摘要 G蛋白偶联受体(Gpcr)是人类基因组中最大的一类受体，可以发出信号。 通过多种转导途径，包括异源三聚体G蛋白和β-拦阻蛋白。阿片受体是GPCRs 其在痛觉中的作用使其成为止痛药的主要药物靶点，如羟考酮和 吗啡。然而，阿片类药物具有极高的滥用潜力，并经常造成致命的副作用，如 呼吸停止和死亡。这些问题的严重性促使人们寻找阿片类药物的替代品进行治疗 疼痛及相关情况。阿片受体激活激活下游效应器，包括多G 蛋白质(Gi1、Gi2、Gi3、GoA、Gob、Gz和Ggustducin)和β-arrestins(β-arrestin1和β-arrestin2)。一位少校 GAP是对阿片受体如何识别不同的转导和功能的不完全理解 通过每条途径传递信号的效果。Kappa阿片受体(KOR)已显示出良好的治疗效果 潜在的，因为它的新的止痛活性-针对KOR的药物不会导致成瘾或导致死亡 由于服用过量的Mu阿片受体激动剂。选择性的KOR拮抗者也被 在治疗成瘾和抑郁症的临床试验中追求的。我实验室的研究是由 总体假设受体-配体/转导分子复合体的大规模结构确定研究将 提供对阿片受体信号的分子水平的洞察，并促进新的设计和优化 可以进一步开发成具有所需行为特征的新药的配体支架。通过结合X- 射线结晶学、低温电子显微镜和分子药理学，我们将阐明KOR的基本机制 配体选择性、受体激活和信号转导。为此，我们将朝以下主要方向努力：(I) 确定不同阿片受体类型之间配体选择性的结构决定因素，(2)确定 不同G蛋白亚型识别的分子基础，以及(Iii)确定负责的结构特征 Arrestin结合的活化态。长期目标是开发受体特异性和途径选择性的探针。 利用基于结构的药物发现和研究个体阿片受体信号在体内的功能。

Project Summary/Abstract G protein-coupled receptors (GPCRs) are the largest class of receptors in the human genome and can signal through multiple transducers, including heterotrimeric G protein and β-arrestins. Opioid receptors are GPCRs whose role in pain sensation has made them primary drug targets for pain medications such as oxycodone and morphine. However, opioids have exceptionally high abuse potential and often cause fatal side effects such as respiratory arrest and death. The magnitude of these problems has led to a search for opioid alternatives to treat pain and related conditions. Activation of opioid receptors activates downstream effectors, including multiple G proteins (Gi1, Gi2, Gi3, GoA, GoB, Gz, and Ggustducin) and β-arrestins (β-arrestin1 and β-arrestin2). A major gap is an incomplete understanding of how opioid receptors recognize different transducers and the functional effects of signaling through each pathway. Kappa opioid receptor (KOR) has displayed promising therapeutic potential because of its novel analgesic activity –drugs that target KOR do not lead to addiction or cause death due to overdose as observed from mu opioid receptor agonists. Selective KOR antagonists have also been pursued in clinical trials for the treatment of addiction and depression. The research in my lab is driven by the overall hypothesis that large-scale structural determination studies of receptor-ligand/transducer complexes will provide molecular-level insights into opioid receptor signaling, and facilitate the design and optimization of novel ligand scaffolds that could be further developed into new drugs with desired behavior profile. By combining X- ray crystallography, Cryo-EM, and molecular pharmacology, we will elucidate fundamental mechanisms of KOR ligand selectivity, receptor activation and signaling. To do so, we will pursue the following main directions: (i) identify structural determinants of ligand selectivity between different opioid receptors types, (ii) identify the molecular basis for different G protein subtypes recognition, and (iii) identify structural features responsible for arrestin-bound activating states. The long-term goal is to develop receptor-specific and pathway-selective probes using structure-based drug discovery and study the function of individual opioid receptor signaling in vivo.