PHOTOTRANSDUCTION IN HEALTH AND DISEASE

摘要 光转导是一个基本的生物学过程，涉及一系列生物化学反应， 感光细胞启动视觉。这项研究计划的长期目标是了解 在正常和疾病状态下的光转导的生化事件的机制。 视紫红质和视锥蛋白是光感受器细胞中的光感受器，在刺激时启动视觉 光。这里的主要重点是视紫红质的结构，功能和功能障碍。视紫红质在 在光传导中起着信号传导的启动作用，在维持健康方面也起着重要的作用 光感受器细胞。视紫红质基因是导致遗传性视网膜疾病的突变热点， 视网膜色素变性（RP）和先天性静止性夜盲症（CSNB），目前还没有治愈或 有效治疗。视紫红质是一种典型的G蛋白偶联受体，因此这里的发现可以 提供了对这个蛋白质超家族的其他成员的见解，这些成员在结构上具有共同点， 行动机制。尽管有丰富的知识可用于视紫红质，差距，在我们的结构和 对受体的分子理解仍然存在，并且对突变的影响的机制描述仍然存在。 导致视觉障碍的光受体是不完整的。关于它的结构、功能和 视锥细胞视蛋白的功能障碍，这是一个次要目标。视紫红质的结构和 将在本提案中审查这一职能。视蛋白必须采用适当的三维结构， 在感光细胞中起作用。在目的1中，一组引起RP和RP的突变体的错误折叠和聚集， 将表征引起蓝锥单色性的锥视蛋白中的突变体，并且所得到的 结果在小鼠模型的视网膜检查。视紫红质在其位点形成超分子结构 在暗视条件下，在感光细胞的杆外节中起作用以执行其功能。在 目的2，这种超分子结构的动力学将被可视化，疾病状态对 将检查这种膜组织。视紫红质的结构被精细地调整以防止激活。 在没有光刺激的情况下。视紫红质的组成活性可导致多种 引起CSNB或RP的表型。在目标3中，由以下原因引起的不同表型的分子起源 将检测引起视紫红质组成型活性的突变。该提案结合了对一项 用创新的生物物理和生化方法回答各种转基因小鼠的问题 在每一个目标中。从我们的研究结果将导致一个更准确的机制框架来理解 该系统在正常条件下的功能和遗传性视网膜疾病中的功能障碍， 为科学探索提供了新的途径。视紫红质基础研究的长期影响 结构和功能将成为靶向治疗和发现新药物靶点的潜力。

Abstract Phototransduction is a fundamental biological process involving a set of biochemical reactions in photoreceptor cells initiating vision. The long-term goal of this research program is to understand the molecular mechanisms underlying the biochemical events in phototransduction under normal and diseased states. Rhodopsin and cone opsins are the light receptors in photoreceptors cells that initiate vision upon stimulation by light. The primary focus here is on rhodopsin structure, function and dysfunction. Rhodopsin plays a central role in phototransduction as the initiator of signaling and also plays an important role in maintaining the health of photoreceptor cells. The rhodopsin gene is a hot spot for mutations causing inherited retinal diseases such as retinitis pigmentosa (RP) and congenital stationary night blindness (CSNB), which currently have no cure or effective treatment. Rhodopsin is a prototypical G protein-coupled receptor and therefore findings here can provide insights on other members of this superfamily of proteins that share commonalities in structure and mechanisms of action. Despite the wealth of knowledge available for rhodopsin, gaps in our structural and molecular understanding of the receptor still exist and a mechanistic description on the effect of mutations in the light receptor causing vision disorders is incomplete. Less is known about the structure, function, and dysfunction of cone opsins, a secondary focus here in one aim. Three aspects of rhodopsin structure and function will be examined in this proposal. Opsins must adopt a proper three-dimensional structure for proper function in photoreceptor cells. In aim 1, the misfolding and aggregation of a set of mutants that cause RP and a mutant in a cone opsin causing blue cone monochromacy will be characterized, and the resulting consequences in the retina of mouse models examined. Rhodopsin forms a supramolecular structure at its site of action in the rod outer segment of photoreceptor cells to carry out its function under scotopic conditions. In aim 2, the dynamics of this supramolecular structure will be visualized and the impact of diseased states on this membrane organization will be examined. The structure of rhodopsin is finely tuned to prevent activation of the receptor in the absence of light stimulation. Constitutive activity of rhodopsin can lead to a variety of phenotypes causing CSNB or RP. In aim 3, the molecular origin of the different phenotypes caused by mutations causing constitutive activity in rhodopsin will be examined. The proposal combines the study of a variety of genetically modified mice with innovative biophysical and biochemical methods to answer questions raised in each aim. Results from our studies will lead to a more accurate mechanistic framework to understand the function of the system under normal conditions and dysfunctions in inherited retinal diseases, which will provide new avenues for scientific inquiry. The long-term impact in studying fundamental aspects of rhodopsin structure and function will be the potential for targeted therapeutics and discovery of novel drug targets.