Regulation of Cyclic GMP Synthesis in Photoreceptors

项目总结 各种先天性视网膜疾病都是“光转导疾病”，由视网膜的异常引起。 CGMP(CGMP)介导的光感受器信号转导机制。中的基本原则之一 光感受器信号和生理是由视网膜鸟苷酸环化酶催化的cGMP合成 (RetGC)，由钙、鸟苷酸环化酶激活蛋白(GCAPs)控制，以及视网膜变性3 (RD3)蛋白质。RetGC活性和/或调节缺陷导致严重形式的先天性失明-Leber 先天性黑色素1(LCA1)和显性视锥-视杆细胞营养不良6(CORD6)。高度的重要性和 RetGC在光感受器信号和存活中的调节的基本原理已经建立，但 一些关键的机制方面仍然没有得到充分的理解。这包括那些蛋白质相互作用 决定其生物学功能的RetGC，当受到影响时，会引发视网膜疾病。这项建议，符合 为NEI的使命提供支持，以支持关于失明眼病、视力障碍和机制的研究 视觉功能的研究是建立在研究光感受器RetGC调节的最新进展基础上的 生理和疾病：1)鉴定对RetGC与GCAPs相互作用至关重要的蛋白质决定因素 和RD3；2)RD3上的RetGC结合域的定位；3)建立第一个小鼠遗传模型 研究RetGC1突变引起的CORD6变性；4)RetGC1基因传递的研究进展 由腺相关病毒(AAV)载体介导；以及5)描绘多种生理后果 导致LCA1和CORD6的RetGC1不同结构域的突变。我们在这里提出了一个广泛的 评估新假说并提供对监管过程的深入机制理解的研究 通过整合蛋白质生物化学、分子生物学、分子遗传学和基因传递来合成cGMP。 目标1将阐述GCAP和RD3调控RetGC的分子机制。目标2将 用一种新开发的方法确定与CORD6相关的RetGC1突变如何触发光感受器死亡 CORD6变性转基因小鼠模型的建立。目标3将寻求更好地理解分子和 RD3调控RetGC活性的细胞机制。通过完成这些特定的目标， 我们希望对RetGC的功能和监管如何定义其 在正常光感受器生理学和先天性视网膜疾病中的作用。

PROJECT SUMMARY Various congenital retinal disorders are “phototransduction diseases”, caused by abnormalities in photoreceptor signaling mechanisms mediated by cyclic cGMP (cGMP). One of the fundamentals in photoreceptor signaling and physiology is cGMP synthesis catalyzed by retinal guanylyl (guanylate) cyclase (RetGC), controlled by calcium, guanylyl cyclase activating proteins (GCAPs), and retinal degeneration 3 (RD3) protein. Defects in RetGC activity and/or regulation cause severe forms of congenital blindness – Leber congenital amaurosis 1 (LCA1) and dominant cone-rod dystrophy 6 (CORD6). The high importance and the basic principles of the RetGC regulation in photoreceptor signaling and survival have been established, yet some key mechanistic aspects remain insufficiently understood. That includes those protein interactions of RetGC that define its biological function and, when affected, trigger retinal diseases. This proposal, conforming to the NEI mission to support research with respect to blinding eye diseases, visual disorders and mechanisms of visual function, is build on recent new advancements in studying RetGC regulation in photoreceptor physiology and disease: 1) identification of protein determinants critical for RetGC interactions with GCAPs and RD3; 2) location of RetGC binding domain on RD3; 3) development of a first mouse genetic model for studying CORD6 degeneration caused by mutation in RetGC1; 4) advancements in RetGC1 gene delivery mediated by adeno-associated viral (AAV) vectors; and 5) delineating multiple physiological consequences of mutations in different structural domains of RetGC1 causing LCA1 and CORD6. We here propose a broad study to evaluate new hypotheses and provide in-depth mechanistic understanding of regulatory processes in cGMP synthesis, by integrating protein biochemistry, molecular biology, molecular genetics and gene delivery. Aim 1 will address the molecular mechanisms underlying RetGC regulation by GCAPs and RD3. Aim 2 will determine how a RetGC1 mutation linked to CORD6 triggers photoreceptor death using a newly developed transgenic mouse model of CORD6 degeneration. Aim 3 will seek better understanding of molecular and cellular mechanisms controlled by RD3 in regulation of the RetGC activity. By completing these specific aims, we expect to reach a deeper and more reliable understanding of how RetGC function and regulation define its role in normal photoreceptor physiology and in congenital diseases of the retina.