Investigation of the molecular basis of rod and cone photoreceptor structure

 描述(申请人提供)：脊椎动物的视力和人类视觉健康取决于视杆和视锥感光细胞外节(OSS)的膜性结构。各种各样的视觉掠夺疾病与OS结构缺陷有关；然而，无论是潜在的疾病病因，还是受体细胞的基本生物学都不是很清楚。特别是，负责产生和稳定成熟的杆状和锥状OS盘结构的分子机制尚不清楚。这项研究的长期目标是充分详细地定义OS架构和更新，以解释缺陷是如何导致视网膜疾病的，并设计有效的治疗策略。目前的目标是确定外周蛋白-2/RDS(P/RDS)如何作为OS膜的组织者发挥作用。这种完整的膜Tetraspanin以一种基本的、尽管机制上不确定的方式来支持视杆细胞和视锥细胞的OS结构，P/RD的遗传突变会导致广泛的进行性疾病，包括视网膜色素变性和黄斑变性。这项研究的第一个目的将确定已知的蛋白质结构/调节决定因素对高度弯曲的膜诱导P/RDS的重要性。第二个目的将检验这一假设，即P/RDS C-末端通常是通过分割可诱导的两亲性螺旋连接在一起的膜，该螺旋可以将OS盘缘系在一起。第三个目标将检验P/rds C-末端结构域的致病突变可以优先影响视锥细胞光感受器的假设。这项工作的成功完成将提高对P/rds蛋白结构功能的认识，阐明P/rds如何产生高曲率膜来形成和稳定OS盘，并将为理解P/rd致病突变如何优先影响视锥(相对于视杆)光感受器提供机制基础。这项工作还可以通过建议新的策略来管理由OS结构的原发病理导致的进行性视网膜退化，从而产生积极的影响。

 DESCRIPTION (provided by applicant): Vertebrate sight and human visual health depend upon the membranous architecture of rod and cone photoreceptor outer segments (OSs). A broad variety of sight-robbing diseases is associated with defects in OS architecture; however, neither the underlying disease etiologies, nor the fundamental biology of the receptor cells is well understood. In particular, the molecular mechanisms responsible for generating and stabilizing the structure of mature rod and cone OS disks are not yet known. The long-term goal of this research is to define OS architecture and renewal in sufficient detail to explain how defects generate retinal disease and design effective therapeutic strategies. The current goal is to determine how peripherin-2/rds (P/rds) functions as an organizer for OS membranes. This integral membrane tetraspanin acts in an essential, though mechanistically uncertain fashion to support OS architecture for both rods and cones, and inherited mutations in P/rds cause a broad range of progressive diseases, including retinitis pigmentosa and macular degenerations. The first Aim of this study will determine the importance of known protein structural/regulatory determinants for P/rds induction of highly curved membranes. The second Aim will test the hypothesis that the P/rds C-terminus is normally membrane associated via partitioning of an inducible amphipathic helix that can function to tether OS disk rims together. The third Aim will test the hypothesis that pathogenic mutations in the P/rds C-terminal domain can preferentially impact cone photoreceptors. Successful completion of the work proposed would improve knowledge of P/rds protein structure-function, clarify how P/rds can generate high curvature membranes to form and stabilize OS disks, and would provide a mechanistic basis for understanding how pathogenic mutations in P/rds preferentially affect cone (vs. rod) photoreceptors. The work could also make a positive impact by suggesting new strategies for managing progressive retinal degenerations that result from primary pathologies in OS structure.