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Structural Dynamics in Rhodopsin Activation and Attenuation

视紫红质激活和衰减的结构动力学

基本信息

批准号：
10611423
负责人：
David L Farrens
金额：
$ 38.5万
依托单位：
OREGON HEALTH & SCIENCE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-05-01 至 2025-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10611423
关键词：
11 cis Retinal Address Affect Affinity Agonist Apoptosis Arrestins Attenuated Binding Cattle Color Visions Complement Complex Computing Methodologies Cone Data Analyses Disease Drug Targeting Enabling Factors Encapsulated Equilibrium Event Exhibits Family Foundations G-Protein-Coupled Receptors GRK1 gene GTP-Binding Proteins Goals Health Human Human Genome Kinetics Ligand Binding Ligands Light Lipids Molecular Molecular Chaperones Molecular Conformation Mutation Night Blindness Nonexudative age-related macular degeneration Opsin Pharmaceutical Preparations Pharmacologic Substance Pharmacological Treatment Phosphorylation Photobleaching Photoreceptors Pigments Play Process Property Proteins Receptor Signaling Refractory Research Research Design Retina Retinal Degeneration Retinal Diseases Retinal Pigments Retinitis Pigmentosa Rhodopsin Role Route Sequence Homology Structure Techniques Testing Time Transducin Variant Vertebrate Photoreceptors Vision Visual Signal Transduction Pathway Work adduct attenuation autosome biophysical analysis chromophore design dimer experimental study insight novel pharmacologic photoactivation receptor small molecule tool uptake

项目摘要

Project Summary A long-term goal of our research is to understand the molecular mechanisms through which G-protein coupled receptors (GPCRs) are activated and attenuated. GPCRs are the largest family in the human genome, and the target of most pharmaceutical drugs. One exception has been rhodopsin – although the first GPCR discovered, it has so far been refractory to direct pharmacological treatments. Here the Kliger and Farrens lab join forces to define the dynamic events and mechanisms involved in the photo-activation of human rhodopsin and cone photopsins, determine how rhodopsin interacts with its ligand, retinal, determine how its function changes with mutations responsible for retinal diseases and determine how these interactions enable, and are modulated by, interactions with its affiliate protein arrestin. Although the structures of retinal, rhodopsin, and arrestin are now known, the dynamic processes that enable them to interact with each other are not. Thus, the types of studies we propose here are required. Specific Aim 1 will determine the photoactivation kinetics of human red and green cone pigments, determine how the activation of human rhodopsin is short-circuited by mutations associated with ADRP, and test how these kinetics are effected by small molecule chaperones used to treat and stabilize misfolded opsins. Specific Aim 2 will determine what role novel receptor conformations play in the process of retinal uptake and release, test if a previously unidentified receptor conformation enables binding of 11-cis retinal (11CR), and expand on our discovery that opsin can transiently linger in an active-like state after releasing all-trans retinal (ATR). Finally, Specific Aim 3 will determine if arrestin binding enables ATR to bind photobleached rhodopsin in equilibrium, and define what effect arrestin binding to rhodopsin dimers has on this phenomenon. Understanding what regulates the process of rhodopsin photoactivation, and retinal uptake and release, and how arrestin regulates these actions is critically important from a health perspective. The retina must accommodate huge variations in these events as it adapts to widely different light conditions, yet aberrations in this process over time are thought to result in the formation of oxidative retinal adducts that promote diseases like atrophic age-related macular degeneration (AMD). Thus, it appears that arrestin must walk a fine line – on the one hand controlling the amount of free retinal released under varying light conditions, and on the other releasing retinal and itself from the receptor at the appropriate time to avoid forming stable rhodopsin-arrestin complexes that can contribute to apoptosis and some forms of retinitis pigmentosa. The work here complements our recent discovery that ATR can exchange in equilibrium with some rhodopsin photoproducts, and recent discoveries by others of non-retinal ligands that bind and stabilize misfolded opsins. These findings dramatically increase the possibility that drugs can be developed to either compete with or enhance retinal binding, thus opening the door for treating this key photoreceptor with pharmacological agents.

项目概要我们研究的长期目标是了解 G 蛋白偶联的分子机制受体（GPCR）被激活和减弱。 GPCR 是人类基因组中最大的家族，大多数药物的靶点。视紫红质是一个例外——尽管第一个 GPCR 发现后，迄今为止直接药物治疗对其无效。 Kliger 和 Farrens 实验室在这里联手定义了涉及的动态事件和机制。人视紫红质和视锥光蛋白的光激活，确定视紫红质如何与其配体相互作用，视网膜，确定其功能如何随着导致视网膜疾病的突变而变化，并确定如何这些相互作用使得与其附属蛋白视紫红质抑制蛋白的相互作用成为可能并受到其调节。虽然视网膜、视紫红质和视紫红质的结构现在已为人所知，其动态过程使它们能够相互之间的互动都不是。因此，我们在这里提出的研究类型是必需的。具体目标 1 将确定人类红色和绿色视锥细胞色素的光活化动力学，确定人类视紫红质的激活如何因 ADRP 相关突变而短路，并测试如何这些动力学受到用于治疗和稳定错误折叠视蛋白的小分子伴侣的影响。具体的目标 2 将确定新的受体构象在视网膜摄取和释放过程中发挥什么作用，测试先前未识别的受体构象是否能够结合 11-顺式视网膜 (11CR)，并扩展我们发现视蛋白在释放全反式视网膜（ATR）后可以短暂地停留在类似活性的状态。最后，特定目标 3 将确定视紫红质抑制蛋白结合是否使 ATR 能够结合光漂白的视紫红质平衡，并定义抑制蛋白与视紫红质二聚体结合对此现象有何影响。了解什么调节视紫红质光活化过程以及视网膜摄取和释放，以及从健康角度来看，抑制蛋白如何调节这些行为至关重要。视网膜必须适应这些事件的巨大变化，因为它适应了广泛不同的光照条件，但像差随着时间的推移，这一过程被认为会导致氧化性视网膜加合物的形成，从而促进疾病例如萎缩性年龄相关性黄斑变性（AMD）。因此，看来视紫红质抑制蛋白必须小心行事—— 一方面控制不同光照条件下释放的游离视网膜的量，另一方面在适当的时间从受体中释放视网膜及其本身，以避免形成稳定的视紫红质抑制蛋白可能导致细胞凋亡和某些形式的视网膜色素变性的复合物。这里的工作补充了我们最近的发现，即 ATR 可以与一些视紫红质进行平衡交换光产物，以及其他人最近发现的能够结合并稳定错误折叠视蛋白的非视网膜配体。这些发现极大地增加了开发药物来竞争或竞争的可能性。增强视网膜结合，从而为用药物治疗这一关键光感受器打开了大门。