Phototransduction in health and disease

光转导在健康和疾病中的作用

• 批准号: 8152765
• 负责人: Paul S Park
• 金额: $ 39.25万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-30 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8152765
• 关键词: Animal Model; Atomic Force Microscopy; Binding; Biochemical; Biochemical Reaction; Biological; Biological Assay; Cattle; Cells; Defect; Degenerative Disorder; Disease; Energy Transfer; Environment; Event; Functional disorder; Future; Genes; Genetic; Goals; Grant; Health; Hot Spot; Human; In Vitro; Inherited; Knockout Mice; Knowledge; Laboratories; Lead; Light; Link; Membrane; Membrane Proteins; Methods; Modeling; Molecular; Motion; Mus; Mutagenesis; Mutation; Night Blindness; Opsin; Pathology; Patients; Phenotype; Photons; Photoreceptors; Phototransduction; Property; RPE65 protein; Receptor Activation; Research; Resolution; Retina; Retinal; Retinal Degeneration; Retinal Diseases; Retinal Dystrophy; Retinitis Pigmentosa; Rhodopsin; Role; Sampling; Series; Signal Transduction; Spectrum Analysis; Structure; System; Technology; Testing; Tissues; Transgenic Mice; United States National Institutes of Health; Vision; Vision Disorders; Visual system structure; Xenopus; base; biological systems; chromophore; combat; dimer; disease-causing mutation; human disease; insight; mouse model; mutant; novel strategies; novel therapeutic intervention; programs; receptor; receptor structure function; response; retinal rods; single molecule; tool

DESCRIPTION (provided by applicant): Scotopic vision is initiated upon capture of a photon of light by rhodopsin molecules present in rod photoreceptor cells. The activation of the light receptor rhodopsin sets into motion a series of biochemical reactions called phototransduction, which leads to the hyperpolarization of the cell. The long-term goal of this research program is to understand the molecular mechanisms underlying the biochemical events in phototransduction under normal and diseased states. The starting point will be structure-function studies of rhodopsin. The importance of this molecule extends beyond its central role in phototransduction. The rhodopsin gene is a hot spot for mutations causing inherited vision disorders and these mutations are the leading cause of autosomal dominant retinitis pigmentosa, a heterogeneous group of inherited retinal degenerative diseases. Despite the wealth of knowledge available for rhodopsin, an accurate mechanism of its action is still unavailable and the mechanism underlying mutations in the light receptor causing vision disorders is unclear. Our immediate goal is to explore emerging ideas about the system that expand on classical dogma; namely, the notion of multiple active states of rhodopsin and the organization of rhodopsin into clusters of dimers. The aims of the proposal are thematically linked around understanding the fundamental molecular principles governing the activity of rhodopsin in normal and diseased conditions in people. In the first aim, we will test the implicit assumption made in most studies that the structure and function of human rhodopsin is similar to that of the receptor from better-studied mammalian species (bovine and mouse) used to understand human disease pathology. In the second aim, we will test the hypothesis that there are multiple active states of the receptor and that at least one of these states leads to constitutive activity in a rhodopsn mutant causing congenital stationary night blindness. In the third aim, we will test a putative rhodopsin dimer model and determine whether receptor oligomerization contributes to the phenotype of a rhodopsin mutant causing autosomal dominant retinitis pigmentosa. Significant technological advances are required to overcome the intrinsic difficulties in studying membrane proteins to observe native structural and molecular details that are important to understand the system. Our proposal utilizes several high-resolution biophysical methods including atomic force microscopy, single-molecule force spectroscopy and Forster resonance energy transfer. The combination of these methods with more traditional biochemical, biophysical, and genetic approaches will overcome the limitations of traditional assays alone and allow us to directly test emerging paradigms about rhodopsin structure and function. The successful testing of these new concepts will lead to a more accurate molecular framework to understand the function of the system under normal conditions and dysfunctions in inherited human disease. PUBLIC HEALTH RELEVANCE: We are in an era of research where technology is giving us access to the smallest details of biological systems. Our proposal takes advantage of these technological advances in order to understand the initial events in vision under normal and diseased states. Our studies will reveal fundamental insights about the visual system and will reveal novel strategies to combat retinal disease.

描述（由申请人提供）：暗视觉是在视杆感光细胞中存在的视紫红质分子捕获光子时启动的。光受体视紫红质的激活引发一系列称为光转导的生化反应，从而导致细胞超极化。该研究计划的长期目标是了解正常和患病状态下光转导生化事件背后的分子机制。起点将是视紫红质的结构功能研究。该分子的重要性超出了其在光转导中的核心作用。视紫红质基因是引起遗传性视力障碍的突变热点，这些突变是常染色体显性遗传性视网膜色素变性的主要原因，这是一组异质性遗传性视网膜退行性疾病。尽管对视紫红质有丰富的知识，但其作用的准确机制仍然未知，并且光受体突变导致视力障碍的机制尚不清楚。我们的近期目标是探索关于扩展经典教条的系统的新兴想法；即，视紫红质的多种活性状态的概念以及将视紫红质组织成二聚体簇的概念。该提案的目标在主题上围绕了解控制人类正常和患病条件下视紫红质活性的基本分子原理相关。第一个目标是，我们将测试大多数研究中隐含的假设，即人类视紫红质的结构和功能与用于了解人类疾病病理学的经过更好研究的哺乳动物物种（牛和小鼠）的受体相似。在第二个目标中，我们将测试以下假设：受体存在多种活性状态，并且这些状态中至少一种会导致视紫红质突变体的组成型活性，从而导致先天性静止性夜盲症。在第三个目标中，我们将测试假定的视紫红质二聚体模型，并确定受体寡聚化是否有助于导致常染色体显性视网膜色素变性的视紫红质突变体的表型。需要重大的技术进步来克服研究膜蛋白的内在困难，以观察对于理解系统很重要的天然结构和分子细节。我们的建议利用了几种高分辨率生物物理方法，包括原子力显微镜、单分子力谱和福斯特共振能量转移。这些方法与更传统的生物化学、生物物理和遗传学方法的结合将克服单独传统测定的局限性，并使我们能够直接测试有关视紫红质结构和功能的新兴范例。这些新概念的成功测试将产生更准确的分子框架，以了解系统在正常条件下的功能和遗传性人类疾病的功能障碍。 公共卫生相关性：我们正处于一个研究时代，技术使我们能够了解生物系统的最小细节。我们的建议利用这些技术进步来了解正常和患病状态下视觉的初始事件。我们的研究将揭示有关视觉系统的基本见解，并将揭示对抗视网膜疾病的新策略。