Formation and New Components of the Usher 2 Protein Complex in Photoreceptors

描述（由申请人提供）：Usher综合征是最常见的视力和听力损失。这种病无药可治。我们的长期目标是了解Usher综合征视网膜变性的分子机制，这将为开发有效的治疗方法奠定坚实的基础。该提案的主要焦点是光感受器中由USH2A，VLGR 1和WHRN组成的蛋白质复合物的形成和新组分。编码这三种蛋白质的基因是Usher综合征2型的致病基因，这是Usher综合征最常见的形式。我们最近的研究表明，Usher 2蛋白复合物位于哺乳动物光感受器的睫状体膜复合物（PMC）。这种蛋白质复合物的缺陷导致PMC周围的超微结构异常，并最终导致感光细胞死亡。然而，这种复合物的形成、组成和生物学功能在很大程度上还不清楚。本研究的中心假设是WHRN作为支架蛋白，与USH2A，VLGR 1和Usher 2蛋白复合物的其他组分相关联，并且这些组分有助于光感受器中整个复合物的功能。为了检验这一假设，将讨论两个具体目标。在具体目标1中，将在体外和体内系统中使用一系列生物化学测定来彻底研究USH2A、VLGR 1和WHRN之间的相互作用。将探讨三元络合物存在的可能性。在具体目标2中，将在光感受器中研究Usher 2蛋白复合物的两个新鉴定的候选组分。这些新成分在该复合物中的功能意义将使用其突变小鼠进一步分析。这项研究将对Usher 2蛋白复合物在光感受器中的功能产生新的认识，这也可能应用于毛细胞。因此，本研究将有助于填补差距在我们的知识的基础上的视网膜变性，也许，听力障碍的Usher综合征的机制，这可能是有价值的未来发展的治疗策略Usher综合征。此外，这项研究将提供一个更好地了解PMC在感光细胞生物学中的作用。 公共卫生相关性：Usher 2多蛋白复合物的缺陷导致Usher综合征2型，这是一种同时伴有视网膜色素变性和先天性听力障碍的疾病。本研究旨在探讨该复合物的形成及其潜在的新组分。这项工作的完成，预计将提供更完整的洞察，这种复杂的生物学功能和疾病的机制，潜在的Usher综合征。

DESCRIPTION (provided by applicant): Usher syndrome is the most common condition with vision and hearing loss. There is no cure for this disease. Our long-term goal is to understand the molecular mechanisms of retinal degeneration in Usher syndrome, which will lay a solid foundation for developing effective therapies for this disease. The main focus of this proposal is the formation and new components of the protein complex composed of USH2A, VLGR1 and WHRN in photoreceptors. The genes encoding these three proteins are the causative genes for Usher syndrome type 2, the most common form of Usher syndrome. Our recent research has demonstrated that the Usher 2 protein complex is located at the periciliary membrane complex (PMC) in mammalian photoreceptors. Defects in this protein complex cause ultra structural abnormalities surrounding the PMC and eventually lead to photoreceptor cell death. However, the formation, composition and biological function of this complex are largely not clear. The central HYPOTHESIS of this study is that WHRN, as a scaffold protein, associates with USH2A, VLGR1 and other components of the Usher 2 protein complex, and that these components contribute to the function of the whole complex in photoreceptors. To test this hypothesis, two specific aims will be addressed. In specific aim 1, interactions among USH2A, VLGR1 and WHRN will be thoroughly studied using a series of biochemical assays in both in vitro and in vivo systems. The possibility of the existence of a ternary complex will be explored. In specific aim 2, two newly identified candidate components of the Usher 2 protein complex will be studied in photoreceptors. The functional significance of these new components in this complex will be further analyzed using their mutant mice. This study will generate new insight into the function of the Usher 2 protein complex in photoreceptors, which may be applied in hair cells as well. Therefore, this study will help fill the gap in our knowledge about the mechanisms underlying retinal degeneration and, perhaps, hearing impairment in Usher syndrome, which might be valuable for the future development of therapeutic strategies for Usher syndrome. Furthermore, this study will provide a better understanding of the role of the PMC in photoreceptor cell biology. PUBLIC HEALTH RELEVANCE: Defects in the Usher 2 multi-protein complex cause Usher syndrome type 2, a condition with both retinitis pigmentosa and congenital hearing impairment. This proposal is to investigate the formation of this complex and its potential new components. Completion of this work is expected to provide more complete insight into the biological function of this complex and the disease mechanism underlying Usher syndrome.