Molecular mechanisms of photoreceptor outer segment morphogenesis

光感受器外节形态发生的分子机制

基本信息

批准号：
10411942
负责人：
Vadim Y Arshavsky
金额：
$ 43.09万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-02-07 至 2023-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10411942
关键词：
Actins Address Adverse effects Amino Acids Binding Binding Proteins CRISPR/Cas technology Cell membrane Cellular biology Cilia Complement Cytoskeleton Data Databases Defect Dominant-Negative Mutation Elements Etiology Functional disorder Future Genes Genetic Transcription Health Knock-out Knockout Mice Light Literature Maintenance Membrane Microscopy Molecular Morphogenesis Mutagenesis Organelles Performance Pharmacology Photoreceptors Phototransduction Process Production Property Proteins Proteomics Publishing Research Resolution Rod Role Sensory Set protein Site Structure Surface Testing Therapeutic Intervention Vertebrate Photoreceptors Vesicle Vision base disorder prevention experimental study extracellular vesicles inherited retinal degeneration light adverse effect mutant peripherin photoreceptor cell outer segment photoreceptor degeneration photoreceptor disc protein complex vesicular release

项目摘要

This proposal addresses one of the most fundamental unsolved problems in vision: the molecular and cellular mechanism responsible for building and maintaining the light-sensitive organelle of vertebrate photoreceptor cells, the outer segment. The outer segment is a ciliary structure filled with a stack of disc membranes, which provide vast surfaces for light capture and harbor proteins comprising the phototransduction machinery. Discs are renewed on a daily basis in order to counteract the adverse effects of light exposure, and the fidelity of disc renewal is critical for maintaining photoreceptor health and normal vision. Previous studies established that photoreceptor discs are formed as serial evaginations of the plasma membrane at the outer segment base. Yet, the molecular mechanisms responsible for performing these membrane transformations remain poorly understood. The research strategy outlined in this proposal is built upon the recently uncovered analogy between disc formation in photoreceptor cells and a fundamental property of many other cilia types - the ability to release small extraciliary vesicles, called ectosomes. The photoreceptor cilium also has an innate ability to release massive amounts of ectosomes. However, in normal photoreceptors this process is suppressed by the disc-specific protein, peripherin-2, which retains the budding membranes at the outer segment base, thereby enabling them to be morphed into discs. The formation of both ciliary ectosomes and photoreceptor discs requires the action of the actin cytoskeleton, and recent evidence suggests that ectosome release also relies on the ESCRT protein complex. Therefore, Aim 1 will explore whether a similar interplay between the actin cytoskeleton and ESCRT proteins is responsible for performing the first steps of photoreceptor disc formation. Aim 2 will explore the mechanism by which peripherin-2 transforms the functional state of the photoreceptor cilium from releasing ectosomes to retaining membranes at the outer segment base and transforming them into discs. Elucidating these mechanisms is critical for advancing our understanding of basic photoreceptor cell biology and pathobiological mechanisms underlying photoreceptor degeneration frequently associated with defects in outer segment morphogenesis.

该提议涉及视力中最基本的未解决问题之一：分子和细胞负责建造和维护脊椎动物感光细胞的光敏细胞器的机制，外部段。外部段是一个充满一堆椎间盘膜的睫状结构，提供光捕获的巨大表面，并掩盖蛋白质，包括光转导机械。光盘已更新每天为了抵消光暴露的不利影响，椎间盘更新的保真度至关重要维持感光受体健康和正常视力。先前的研究表明，光感受器椎间盘是形成是外部片段基部质膜的串行逃避。但是，分子机制负责执行这些膜转化的理解仍然很少。研究策略该提案中概述的构建是基于感光细胞中最近未发现的盘形成的类比以及许多其他纤毛类型的基本特性 - 释放小囊泡的能力，称为外生体。光感受器纤毛还具有释放大量过脑体的先天能力。然而，在正常的光感受器中将萌芽的膜保留在外部片段基部，从而使它们能够变成圆盘。睫状外神经体和光感受器椎间盘的形成需要肌动蛋白细胞骨架的作用，最近的证据表明，外胞体释放也取决于ESCRT蛋白复合物。因此，瞄准 1将探讨肌动蛋白细胞骨架和ESCRT蛋白之间的类似相互作用是否负责执行光感受器盘形成的第一步。 AIM 2将探讨该机制外围蛋白-2将光感受器纤毛的功能状态从释放的外胞胞体转变为保留外部片段的膜并将其转化为圆盘。阐明这些机制至关重要为了促进我们对基本感光细胞生物学和病理生物学机制的理解光感受器变性通常与外部段形态发生中的缺陷有关。