The differential behavior of Prph2/Rom1 in rods and cone contributes to Prph2-associated disease heterogeneity

项目摘要 外周蛋白2（PRPH 2）突变占遗传性视网膜疾病（IRD）的重要部分。 阐明PRPH 2在光感受器形态发生和边缘形成中的作用对于理解PRPH 2在光感受器形态发生和边缘形成中的作用是至关重要的。 单一蛋白质的突变可能导致如此多样的病理组， 色素变性（RP）至模式性营养不良（PD）和黄斑变性（MD）。即使是家族内 突变可以表现出显着程度的表型变异性，证明了复杂的性质，其中PRPH 2 功能协调发展的我在本申请中的目的是推进我们目前对PRPH 2在外部环境中的作用的认识。 节段（OS）的形成，以便更好地了解疾病的发病机制和未来 制定有效的治疗策略。多年来，我们的实验室已经开发了一个广泛的工具箱， 在体外和体内突变模型，目前正在探索创新的成像技术，以进一步我们的 了解Prph 2在OS环境中的作用。到目前为止，已经确定该协会 Prph 2与其同源物Rod OS蛋白1（Rom 1）之间的差异显著影响了 在患者中观察到变异性，降低Rom 1水平可改变严重的Prph 2相关PD表型 更温和的RP。此外，已知Prph 2在椎间盘边缘的适当功能取决于适当的 Prph 2-寡聚体和Prph 2/Rom 1-复合物的复合物组装。这次调查的重点 了解Prph 2和Rom 1在视杆细胞和视锥细胞中的不同功能， Prph 2同源复合物和Prph 2/Rom 1杂合复合物的形成/运输以及Prph 2突变的影响 在这些过程中。我们提出了两个目标来实现这些目标：目标1将评估ROM 1在以下方面的作用： 视锥细胞及其调节Prph 2疾病表型的机制。通过消除或过度表达 Rom 1在Prph 2疾病模型中，我们将进行仔细的生化，结构和功能分析， 评估表型差异，因为它们涉及复杂的组装和OS运输。目标2将调查 Prph 2在视杆细胞与视锥细胞中的差异行为中相互作用伙伴的作用。为了使交通正常 Prph 2在OS中发挥作用，形成膜微域来组织和容纳蛋白质网络， 对于形成杆中的封闭边缘和锥体中的开放薄片/边缘是必需的/特定的。在这一目标下， 我们将确定关键的Prph 2结合伙伴，并确定这些相互作用如何不同的杆， 圆锥体。这些研究的结果将阐明Prph 2和Rom 1在视杆细胞和视锥细胞中的特定功能， 确定调节Rom 1如何影响疾病表型，并将进一步了解 Prph 2在杆状细胞中以封闭的边缘结构存在，在圆锥细胞中以开放的边缘结构存在。由于缺乏有效的 Prph 2相关疾病的治疗，这些研究是必不可少的，并引起人们对Rom 1作为 一种用于未来开发有效治疗策略的常见疾病调节剂。

PROJECT SUMMARY Mutations in Peripherin 2 (PRPH2) account for a significant portion of inherited retinal diseases (IRD). Delineating the role of PRPH2 in photoreceptor morphogenesis and rim formation is vital to understand how mutations in a single protein could contribute to such diverse group of pathologies, ranging from retinitis pigmentosa (RP) to pattern dystrophy (PD) and macular degeneration (MD). Even patients with intrafamilial mutations can exhibit a notable degree of phenotypic variability, attesting to the complex nature in which PRPH2 functions. My objective in this application is to advance our current knowledge of the role of PRPH2 in outer segment (OS) formation in order to have a better understanding of disease pathogeneses and for future development of effective therapeutic strategies. Over the years, our lab has developed an extensive toolbox of in vitro and in vivo mutant models, and are currently exploring innovative imaging techniques to further our understanding of the role of Prph2 in OS landscape. Thus far, it has been determined that the association between Prph2 and its homologue, Rod OS Protein 1 (Rom1), contributes significantly to the phenotypic variability observed in patients and that lowering Rom1 levels could shift a sever Prph2-assocaited PD phenotype to milder RP. Furthermore, it is know that the proper function of Prph2 at the disc rim is contingent upon proper complex assembly of Prph2-oligomers and Prph2/Rom1-complexes. The central focus of this investigation is to understand how Prph2 and Rom1 function differently in rods and cones with particular interest in Prph2 homo- and Prph2/Rom1 hetero-complex formation/trafficking, and the effects of Prph2 mutations on these processes. We propose two aims to address these goals: Aim 1 will assess the role of Rom1 in cones and the mechanism by which it modulates Prph2-disease phenotypes. By eliminating or overexpressing Rom1 in Prph2-disease models, we will conduct careful biochemical, structural, and functional analyses to assess phenotypic differences, as they pertain to complex assembly and OS trafficking. Aim 2 will investigate the role of interacting partners in the differential behavior of Prph2 in rods vs cones. In order to properly traffic and function in the OS, Prph2 forms membrane microdomains to organize and house a network of proteins that are necessary/specific for the formation of the closed rims in rods and open lamellae/rims in cones. In this aim, we will identify critical Prph2 binding partners and determine how these interactions differ between rods and cones. The outcomes of these studies will elucidate the specific function of Prph2 and Rom1 in rods and cones, determine how modulating Rom1 affects disease phenotypes, and will further our understanding of the role of Prph2 in the closed rim structure in rods and the open rim structures in cones. Given the lack of effective treatments for Prph2-associated diseases, these studies are essential and bring attention to the role of Rom1 as a common disease modulator for future development of effective therapeutic strategies.