Mechanisms of photoreceptor disc maturation

感光盘成熟的机制

• 批准号: 9973539
• 负责人: Vadim Y Arshavsky
• 金额: $ 49.39万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/9973539
• 关键词: 3-Dimensional; Address; Affect; Anatomy; Animals; Biology; Biotinylation; Blindness; Cadherins; Cell membrane; Cellular biology; Cilia; Cleaved cell; Cone; Cyclic GMP; Data; Defect; Disease; Dynamin; Electron Microscopy; Etiology; Extracellular Domain; Individual; Inherited; Intervention; Knock-in Mouse; Knock-out; Knockout Mice; Lateral; Lead; Light; Link; Mammals; Membrane; Metalloproteases; Molecular; Morphogenesis; Morphology; Mus; Organelles; Pharmacological Treatment; Pharmacology; Phenotype; Photons; Photoreceptors; Precipitation; Prevalence; Prevention; Process; Property; Protein Isoforms; Proteins; Retinal Cone; Retinal Degeneration; Rod; Role; Signal Transduction; Structure; Structure of retinal pigment epithelium; Surface; Testing; Time; Tomogram; Vertebrate Photoreceptors; Vesicle; Vision; Vision Disorders; Vision research; base; conditional knockout; design; experimental study; extracellular; fascinate; inherited retinal degeneration; malformation; mutant; peripherin; photoreceptor degeneration; photoreceptor disc; prevent; reconstruction; response; retinal rods; scaffold; tomography; tool

The experiments described in this proposal address one of the most fascinating unanswered questions in vision research regarding the molecular mechanisms responsible for photoreceptor outer segment morphogenesis. The outer segment is a ciliary organelle that produces electrical signals in response to capturing light. A unique morphological feature of the outer segment is that it is filled with a stack of flattened membrane discs providing vast surfaces for photon capture and signal amplification. The functional significance of this anatomical arrangement has been recognized for a very long time, yet our understanding of how discs are built at the molecular level remains frustratingly rudimentary. This application addresses several poorly understood aspects of photoreceptor disc morphogenesis, related to the processes of disc expansion, alignment and enclosure. Our preliminary data show that the edges of newly formed discs contain two distinct types of extracellular links: one connecting discs with the inner segment plasma membrane and another connecting disc edges between themselves. Experiments described in Aims 1 and 2 will be devoted to determining the protein composition of each link type and elucidating their specific roles in supporting the high fidelity of disc elongation and stacking. Aim 3 will focus on the final step in disc maturation consisting of its scission from the outer segment plasma membrane. We will address whether disc scission takes place exclusively in rods and explore molecular players involved in this process. Experiments described in this application will employ versatile molecular tools combined with the state-of-the-art three dimensional electron microscopy tomographic analysis of the outer segment structure. Addressing these mechanistic questions is essential for advancing our basic understanding of photoreceptor cell biology, as well as elucidating the pathophysiological mechanisms underlying inherited blindness frequently associated with defects in outer segment morphogenesis.

本提案中描述的实验涉及视力中最迷人的未解决问题之一 有关负责光感受器外部段形态发生的分子机制的研究。这 外部段是一种睫状细胞器，可用于捕获光的响应。一个独特的 外部段的形态特征是它充满了一堆扁平的膜盘，可提供广阔 光子捕获和信号扩增的表面。该解剖学布置的功能意义具有 被认可了很长时间，但是我们对分子层如何建造光盘的理解仍然存在 令人沮丧的基本。该应用程序解决了光感受器盘的几个知识不理的方面 形态发生，与椎间盘扩展，对齐和外壳的过程有关。我们的初步数据显示 新形成的光盘的边缘包含两种不同类型的细胞外链接：一个与圆盘连接的 内部段质膜和它们之间的另一个连接圆盘边缘。描述的实验 在目标1和2中，将致力于确定每种链接类型的蛋白质组成并阐明其 在支持圆盘伸长和堆叠的高忠诚度中的特定角色。 AIM 3将重点放在光盘中的最后一步 其成熟由外部片段质膜组成。我们将解决光盘是否 分裂仅在杆中进行，并探索参与此过程的分子参与者。实验 本应用中描述的将采用多功能分子工具与最先进的三个 外部段结构的尺寸电子显微镜断层扫描分析。解决这些 机械问题对于促进我们对感光细胞生物学的基本理解以及 阐明经常与缺陷有关的遗传失明的病理生理机制 外部段形态发生。