The Role of TULP1 in Photoreceptor Cells

TULP1 在感光细胞中的作用

• 批准号: 8228002
• 负责人: STEPHANIE A HAGSTROM
• 金额: $ 39.25万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2016-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8228002
• 关键词: Actins; Address; Affect; Architecture; Attention; Binding; Bioinformatics; Biological Assay; Biology; Blindness; Carrier Proteins; Cellular Membrane; Complement; Complex; Data; Defect; Development; Disease; Dissection; Dyes; Dynamin I; Electron Microscopy; Genes; Goals; Grant; Human; Image; Immunohistochemistry; Immunoprecipitation; In Situ; Individual; Inherited; Isoelectric Focusing; Label; Lasers; Ligands; Liquid Chromatography; Membrane; Membrane Protein Traffic; Methods; Microdissection; Microscopy; Modeling; Molecular; Movement; Mus; Mutation; Neurons; Opsin; Pathway interactions; Perfusion; Phenotype; Phospholipids; Photoreceptors; Physiological; Play; Positioning Attribute; Presynaptic Terminals; Protein Binding; Proteins; Proteomics; Publishing; Recovery; Research Project Grants; Retina; Retinal; Retinal Degeneration; Retinal Diseases; Retinitis Pigmentosa; Rhodopsin; Role; Site; Slice; Structure; Surveys; Synapses; Synaptic Membranes; Synaptic Vesicles; System; Technology; Time; Tissues; Transport Process; Transport Vesicles; Vertebrate Photoreceptors; Vesicle; Wild Type Mouse; Work; base; crosslink; design; early onset; extracellular; in vivo; insight; malformation; mutant; photoreceptor degeneration; protein crosslink; protein transport; public health relevance; research study; tandem mass spectrometry; trafficking

DESCRIPTION (provided by applicant): Retinitis pigmentosa (RP) incorporates a large number of inherited retinal disorders characterized by photoreceptor degeneration. RP is genetically and phenotypically heterogeneous, affecting over 1 million individuals worldwide. Mutations in a gene called TULP1 underlie an early-onset and severe form of autosomal recessive RP. Tulp1 is a protein exclusive to photoreceptor cells, and although the function of Tulp1 remains elusive, there is evidence from the murine model lacking Tulp1 that it plays a role in intracellular protein movement in multiple compartments of the photoreceptor. In tulp1-/- mice, prior to photoreceptor degeneration, rod and cone opsins are mislocalized, and rhodopsin-bearing extracellular vesicles accumulate around the inner segment (IS), indicating that Tulp1 is necessary for the transport of proteins to the outer segment (OS). These mice also have a synaptic malformation that precedes photoreceptor degeneration and most likely interferes with the proper development of post-receptoral neurons. The absence of Tulp1 results in abnormalities that affect structure and function in multiple retinal sites, as well as causing distinct abnormalities in separate photoreceptor compartments. This suggests that it either performs a general role throughout the photoreceptor or participates in multiple distinct pathways. Based on our published work and preliminary data, the central hypothesis of this proposal is that Tulp1 is a component of the molecular machinery involved in the vesicular movement of proteins in two photoreceptor cell compartments. Our long-term objectives are to understand the physiological function of TULP1 and the pathogenic mechanism responsible for retinal degeneration associated with TULP1 mutations. Experiments designed in Aim 1 will identify Tulp1 interacting partners by proteomic analysis, comparing IS-specific to synaptic-specific interactomes. In Aim 2, molecular dissections of the IS and synapse lacking Tulp1 and expressing mutant forms of TULP1 that cause RP will be conducted to probe for structural or spatial disturbances. Attention will focus on proteins that bind Dynamin-1, a neuronal-specific protein that is essential for vesicular trafficking. Elaborating on the Tulp1/Dynamin-1/Actin interaction, which we believe composes the core of Tulp1 functional complexes, will unlock the mechanism of action of Tulp1. Aim 3 will analyze vesicle cycling in the tulp1-/- photoreceptor synapse. This will be accomplished using styryl dye photoconversion followed by electron microscopy. At the successful completion of this work, we will position Tulp1 in a functional context and define its mechanism of action. Our results will provide insight into the functional organization of photoreceptor protein transport pathways, as well as insight into the perturbation of retinal function associated with TULP1 mutations. Finally, this project has potential for significantly impacting an important aspect of photoreceptor biology relevant to human retinal disease. PUBLIC HEALTH RELEVANCE: The goal of this research project is to identify the function of Tulp1, a photoreceptor-specific protein proposed to be involved in protein movement. Mutations in TULP1 cause an early-onset and severe form of retinitis pigmentosa, an inherited form of blindness. Results will provide insight into the pathological mechanisms causing photoreceptor degeneration and significantly impact an important aspect of photoreceptor biology relevant to human retinal disease.

描述（由申请人提供）：视网膜色素变性（RP）合并了大量以感光细胞变性为特征的遗传性视网膜疾病。RP是遗传和表型异质性，影响全球超过100万人。TULP 1基因的突变是常染色体隐性遗传RP的早发和严重形式的基础。Tulp 1是光感受器细胞独有的蛋白质，尽管Tulp 1的功能仍然难以捉摸，但缺乏Tulp 1的小鼠模型有证据表明，它在光感受器的多个隔室中的细胞内蛋白质运动中发挥作用。在tulp 1-/-小鼠中，在光感受器变性之前，视杆和视锥视蛋白被错误定位，并且具有视紫红质的细胞外囊泡在内节（IS）周围积聚，这表明Tulp 1对于将蛋白质运输到外节（OS）是必需的。这些小鼠也有一个突触畸形，感光细胞变性之前，最有可能干扰后受体神经元的正常发育。Tulp 1的缺失导致影响多个视网膜部位的结构和功能的异常，以及在单独的感光细胞室中引起明显的异常。这表明它在整个光感受器中发挥一般作用，或者参与多个不同的途径。基于我们已发表的工作和初步数据，这一提议的中心假设是Tulp 1是参与两个感光细胞隔室中蛋白质囊泡运动的分子机制的组成部分。我们的长期目标是了解TULP 1的生理功能和与TULP 1突变相关的视网膜变性的致病机制。目的1中设计的实验将通过蛋白质组学分析确定Tulp 1相互作用的伴侣，比较IS特异性与突触特异性相互作用组。在目标2中，将进行IS和缺乏Tulp 1并表达引起RP的TULP 1突变形式的突触的分子解剖以探测结构或空间干扰。注意力将集中在结合发动蛋白-1的蛋白质上，发动蛋白-1是一种神经元特异性蛋白质，对囊泡运输至关重要。详细阐述Tulp 1/Dynamin-1/Actin相互作用，我们认为它构成了Tulp 1功能复合物的核心，将解开Tulp 1的作用机制。目的3将分析tulp 1-/-光感受器突触中的囊泡循环。这将使用苯乙烯基染料光转换，然后通过电子显微镜来完成。在这项工作的成功完成，我们将定位Tulp 1在一个功能的上下文中，并定义其作用机制。我们的研究结果将提供深入了解光感受器蛋白转运途径的功能组织，以及深入了解与TULP 1突变相关的视网膜功能的扰动。最后，该项目有可能显著影响与人类视网膜疾病相关的光感受器生物学的一个重要方面。 公共卫生关系：该研究项目的目标是确定Tulp 1的功能，Tulp 1是一种光感受器特异性蛋白，被认为参与蛋白质运动。TULP 1的突变会导致早发性和严重的视网膜色素变性，这是一种遗传性失明。研究结果将为深入了解导致光感受器变性的病理机制提供帮助，并对与人类视网膜疾病相关的光感受器生物学的一个重要方面产生重大影响。