Structural Dynamics in Rhodopsin Activation and Attenuation

视紫红质激活和减弱的结构动力学

• 批准号: 9920141
• 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
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9920141
• 关键词: 11 cis Retinal; Address; Affect; Affinity; Agonist; Apoptosis; Arrestins; Attenuated; Binding; Cattle; Color Visions; Complement; Complex; Computing Methodologies; Cone; Data; Disease; Drug Targeting; 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; Pharmacology; 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; biophysical analysis; chromophore; design; dimer; experimental study; insight; novel; photoactivation; receptor; small molecule; tool; uptake

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.

项目摘要 我们研究的长期目标是了解G蛋白耦合的分子机制 受体（GPCR）被激活并减弱。 GPCR是人类基因组中最大的家庭，并且 大多数药物的靶标。一个例外是视紫红质 - 尽管第一个GPCR 发现，直到直接的药物治疗是难治性的。 在这里，克莱格和法伦斯实验室联手定义了涉及的动态事件和机制 人类视紫红质和锥形光的照片激活，确定视紫红质与配体相互作用的方式， 视网膜，确定其功能如何随着负责残留疾病的突变而变化，并确定如何 这些相互作用可以使其与其关联蛋白停滞蛋白的相互作用进行调节。虽然 现在已知视网膜，视紫红素和逮捕蛋白的结构，使它们能够能够 彼此互动不是。这是我们提出的研究类型。 特定的目标1将确定人红色和绿色锥体色素的光激活动力学，确定 如何通过与ADRP相关的突变来短路人类视紫红质的激活，并测试如何 这些动力学受到用于治疗和稳定错误折叠蛋白的小分子伴侣的影响。具体的 AIM 2将确定在视网膜摄取和释放过程中，新型新受体构象在 测试先前未识别的受体会议是否可以使11盘视网膜（11CR）结合并扩展 我们发现，在进一步释放出全型跨性别后，OPSIN可以暂时徘徊在活跃状态（ATR）。 最后，特定的目标3将确定逮捕蛋白结合是否使ATR结合光漂白的视紫红质 平衡，并确定与视紫红质二聚体结合的影响对这种现象的影响。 了解什么调节了视紫红质光活化的过程，视网膜吸收和释放，以及 从健康的角度来看，逮捕素如何调节这些行动至关重要。视网膜必须 这些事件的适应性巨大变化，因为它适应了广泛不同的光条件，但畸变 随着时间的流逝，这个过程会导致形成促进疾病的氧化残留加合物 像萎缩性年龄相关的黄斑变性（AMD）。那看来，逮捕者必须走一条细线 - 一只手控制在不同的光条件下释放的自由残留量，另一只手 在适当的时间从接收器中释放视网膜，以避免形成稳定的视流蛋白 - arrestin 可以导致细胞凋亡和某些形式的视网膜炎的复合物。 这里的工作完成了我们最近的发现，即ATR可以与某些Rhodopsin平衡交换 光产物以及其他人最近发现的非视网膜配体结合和稳定错误折叠的Opsins的发现。 这些发现极大地增加了可以开发出与竞争或 增强视网膜结合，从而为使用药剂剂处理该关键的光感受器打开门。