Mechanisms and Cellular Function of Opioid Receptor Endocytosis

摘要 阿片和儿茶酚胺受体是神经生理学和行为的关键调节器，并且很重要。 治疗药物和滥用药物的目标。这些受体都属于G蛋白偶联受体(GPCR)。 超家族，是动物体内表达的最大的信号受体，也是一类非常重要的药物 目标。GPCRs通过变构传递信号，并在配体诱导的激活后被广泛调控 磷酸化、内吞作用，并与一类称为拦阻蛋白的细胞质接头蛋白相互作用。 这些监管过程对成瘾药物的行为至关重要，通常情况下 重复给药或长期给药，有证据表明 药物对这些过程的影响。目前的研究计划集中在阐明基本的 这种选择性监管的机制基础。在上一个资助期，我们描述了药物选择性 阿片类药物从细胞质中招募功能相关的GPCRK的生化模式 感受器。我们还确定了一种离散形式的有偏见的药物作用的证据，这是由 受体激活的亚细胞位置。我们还发现了细胞芳香化的一种独特机制 不依赖于受体磷酸化的调节。拟议的研究旨在扩大 这一基础研究工作的目标是发展新的理解，可以利用 治疗效果。具体地说，我们建议(1)定义激动剂选择性的变构基础 阿片受体的磷酸化；(2)阿片相关腺酰环化酶的定位和转运 (3)确定β-arrestin在阿片类药物识别中是否具有非磷酸化作用。

Abstract Opioid and catecholamine receptors are key regulators of neurophysiology and behavior, and are important targets of therapeutic and abused drugs. These receptors all belong to the G protein-coupled receptor (GPCR) superfamily, the largest group of signaling receptors expressed in animals and a very important class of drug targets. GPCRs signal by allostery and are extensively regulated after ligand-induced activation by phosphorylation, endocytosis and interacting with a class of cytoplasmic adaptor proteins called arrestins. These regulatory processes are critically important to the actions of addictive drugs, which are typically administered repeatedly or over a prolonged period, and there is evidence for considerable diversity of the effects of drugs on these processes. The present research program is focused on elucidating the fundamental mechanistic basis of such selective regulation. In the previous funding period, we delineated drug-selective biochemical modes by which a functionally relevant GPCR kinase is recruited from the cytoplasm by opioid receptors. We also identified evidence for a discrete form of biased drug action determined by differences in the subcellular location of receptor activation. We also discovered a distinct mechanism of cellular arrestin regulation that defined by being independent of receptor phosphorylation. The proposed studies seek to extend this fundamental research effort with the goal of developing new understanding that can be leveraged for therapeutic benefit. Specifically, we propose to (1) Define an allosteric basis for agonist-selective phosphorylation of opioid receptors; (2) Delineate localization and trafficking of opioid-relevant adenylyl cyclase isoforms; and (3) Determine if β-arrestin has a phosphorylation-independent role in opioid drug discrimination.