Understanding Photoreceptor Trafficking Pathways to the Outer Segment

了解光感受器外段运输途径

• 批准号: 10570235
• 负责人: Jillian Nydam Pearring
• 金额: $ 45.04万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10570235
• 关键词: Affect; Afferent Neurons; Architecture; Biological; Biological Assay; Biotinylation; Blindness; Bypass; Cell membrane; Cells; Cilia; Communities; Defect; Dependence; Destinations; Detection; Disease; Ensure; Future; G-Protein-Coupled Receptors; Gene Delivery; Goals; Golgi Apparatus; Inherited; Injury; Integral Membrane Protein; Knowledge; Label; Light; Lipids; Membrane; Membrane Proteins; Molecular; Mus; Natural regeneration; Opsin; Organelles; Organoids; Pathogenicity; Pathway interactions; Patients; Persons; Photons; Photoreceptors; Positioning Attribute; Process; Protein Biosynthesis; Proteins; Rapid screening; Retina; Retinal Cone; Retinal Diseases; Retinal Dystrophy; Retinitis Pigmentosa; Rhodopsin; Rod; Rod Outer Segments; Route; Sensory; Shapes; Signal Transduction; Signaling Protein; Site; Sorting; Stargardt' s disease; Structural Protein; System; Techniques; Therapeutic; Travel; Vertebrate Photoreceptors; Vision; absorption; alpha helix; cone-rod dystrophy; cyclic-nucleotide gated ion channels; in vivo; insight; novel; novel therapeutic intervention; peripherin; regenerative approach; response; retinal rods; sensor; stem cells; trafficking

ABSTRACT The first step of vision takes place in the retina where light is captured by the outer segment organelle of rod and cone photoreceptors. The outer segment is a modified primary cilium that contains a stack of flat disc-shaped membranes. This structural arrangement maximizes light detection by forcing photons to pass through hundreds of membrane layers densely packed with the light absorbing protein, opsin. A byproduct of light absorption is photooxidative damage, which the photoreceptor overcomes by continuously replacing its entire membrane-rich outer segment with new protein and lipid material. Defects in outer segment trafficking, formation, and function ultimately result in photoreceptor cell loss and cause a broad spectrum of inherited retinal dystrophies including retinitis pigmentosa, cone-rod dystrophy and Stargardt disease. It is now well established that photoreceptors utilize multiple trafficking pathways to deliver structural and signaling proteins to the light-sensitive outer segment organelle; however, how these pathways are coordinated, the molecular processes regulating delivery, why a cargo chooses a specific route remains largely unknown. The goals of our proposal are to investigate the trafficking pathways of outer segment membrane cargos that reside within the discs (rhodopsin), the disc rims (peripherin-2 and ABCA4) and the plasma membrane surrounding the discs (CNG channel). This comprehensive approach will allow us to understand shared and divergent features between specific trafficking pathways as well as build a complete overview of intracellular routes to the outer segment. Our aims utilize proximity labeling approaches to uncover transport partners in vivo as well as gene delivery techniques to rapidly screen candidates for targeting defects and uncover signals governing conventional and unconventional delivery to the outer segment in mouse rods. Completion of our aims will provide insight into how outer segment trafficking pathways cooperate to deliver the structural and functional proteins necessary to form the light-sensing outer segment organelle as well as how these processes fail during disease. Looking forward, our proposal aims to provide fundamental knowledge about membrane trafficking to sensory cilia in general as well as help to inform future therapeutic strategies for patients suffering from inherited blindness.

抽象的 视觉的第一步发生在视网膜，光线被视网膜的外节细胞器捕获。 视杆细胞和视锥细胞光感受器。外段是经过修饰的初级纤毛，其中包含一堆扁平的 盘状膜。这种结构布置通过迫使光子 穿过数百层紧密包裹着光吸收蛋白视蛋白的膜层。一个 光吸收的副产品是光氧化损伤，光感受器可以通过以下方式克服光氧化损伤： 不断地用新的蛋白质和脂质材料替换其整个富含膜的外部部分。 外节运输、形成和功能的缺陷最终导致感光细胞损失 并引起广泛的遗传性视网膜营养不良，包括色素性视网膜炎、锥杆状视网膜炎 营养不良和斯塔加特病。现在已经确定光感受器利用多重运输 将结构蛋白和信号蛋白传递到光敏感外节细胞器的途径； 然而，这些途径是如何协调的，调节传递的分子过程，为什么货物 选择具体路线仍然很大程度上未知。我们提案的目标是调查 驻留在视盘内的外节膜货物的贩运途径（视紫红质），视盘 边缘（peripherin-2 和 ABCA4）和椎间盘周围的质膜（CNG 通道）。这 综合方法将使我们能够理解特定之间的共同特征和不同特征 运输途径以及建立细胞内外段路线的完整概述。我们的 目标利用邻近标记方法来发现体内的运输伙伴以及基因传递 快速筛选候选者以寻找目标缺陷并发现控制传统信号的技术 以及非常规地输送到小鼠杆的外段。完成我们的目标将提供 深入了解外段贩运途径如何合作以提供结构和功能 形成光传感外段细胞器所必需的蛋白质以及这些过程如何失败 患病期间。展望未来，我们的提案旨在提供有关膜的基础知识 一般情况下转运至感觉纤毛并有助于为患者提供未来的治疗策略 患有遗传性失明。