STRUCTURE AND FUNCTION RELATIONSHIP OF CONE CYCLIC NUCLEOTIDE-GATED CHANNEL

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 光感受器环核苷酸门控(CNG)通道是光信号转导所必需的。编码锥体CNG通道亚单位的基因突变与人类锥体疾病高度相关。视锥CNG通道突变占色觉减退、早发性黄斑变性和进行性视锥细胞营养不良患者的70%。然而，突变导致锥体缺陷的机制尚不清楚，目前我们对锥体CNG通道的结构和功能调节的了解也非常有限。这主要是由于在视杆优势的哺乳动物视网膜中研究视锥系统的困难。我们发现，在转录因子神经视网膜亮氨酸拉链缺陷小鼠(NRL基因敲除小鼠)的视锥优势视网膜中，锥体CNG通道表达旺盛，而杆CNG通道缺失。因此，我们证明了NRL基因敲除小鼠的视网膜是研究哺乳动物锥体CNG通道的独特工具。本研究计划利用该小鼠模型，通过多种生化方法测定天然锥体CNG通道的生化成分和性质。这项研究还旨在通过评估锥体CNG通道与视网膜钙结合蛋白钙调蛋白和钠-钾-钙交换器NCKX2的关系来了解其调节作用。此外，还将通过鉴定锥体CNG通道的相互作用蛋白来探讨其功能调节。这将通过使用多重亲和纯化和质谱分析来实现。这项研究的长期目标是阐明突变相关锥体疾病的机制，目的是确定潜在的锥体疾病治疗措施。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Photoreceptor cyclic nucleotide-gated (CNG) channel is essential to phototransduction. Mutations in genes encoding cone CNG channel subunits are highly linked to human cone diseases. Mutations in cone CNG channel account for 70% of patients with achromatopsia, early-onset macular degeneration, and progressive cone dystrophy. However, the mechanisms by which mutations result in cone defects are unknown and our current understanding of the structure and functional modulation of cone CNG channel is very limited. This is primarily due to the difficulty of investigating the cone system in a rod dominant mammalian retina. We have shown robust expression of the cone CNG channel and lack of the rod CNG channel in the cone-dominant retina of mice deficient in the transcription factor neural retina leucine zipper (Nrl knockout mice). Thus we have demonstrated that the retina of Nrl knockout mice is a unique tool to study cone CNG channel in mammals. This research program is to utilize this mouse model to determine the biochemical components and properties of the native cone CNG channel by using multiple biochemical approaches. The proposed research is also to understand the modulation of cone CNG channel by evaluating its associations with the calcium binding protein calmodulin and the sodium-potassium-calcium exchanger NCKX2 in retina. The functional modulation of cone CNG channel also will be explored by identifying its interacting proteins. This will be achieved by using multiple affinity purification and mass spectrometry analysis. The long-term goal of this research is to elucidate the mechanism of the mutation-associated cone diseases with the objective of identifying potential therapeutic interventions for the cone diseases.