CELLULAR PROCESSES IN PHOTORECEPTOR CELLS

感光细胞中的细胞过程

• 批准号: 2161211
• 负责人: DAVID S WILLIAMS
• 金额: $ 16.5万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-09-30 至 1998-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2161211
• 关键词: Drosophilidae; Xenopus; actin binding protein; actins; calpain; cell biology; chemical binding; enzyme mechanism; enzyme substrate; guanylate cyclase; histogenesis; laboratory mouse; laboratory rabbit; laboratory rat; mutant; myosins; phosphodiesterase inhibitors; protease inhibitor; proteolysis; rod cell; visual photoreceptor

The long term goal of this research is to understand the structure and function of the phototransductive compartment of photoreceptor cells. The proposed plan is to study the actin cytoskeleton and the calpain system in this compartment. Both appear to play critical roles in photoreceptor structure and function. Biochemical and cell biological procedures will be used. I. Actin-binding proteins in the phototransductive compartment. The goal of this section is to address the regulation and function of two actin-binding proteins: one from mammalian rod outer segments, the other from Drosophila rhabdomeres. In photoreceptor outer segments, the actin~cytoskeleton plays an essential role in disk membrane renewal. It also appears to provide a binding site for guanylate cyclase, and thus may help regulate the recovery of the cell to its dark-adapted state. Binding-studies will be used to determine the nature of the binding between f-actin and guanylate cyclase, and its effect on guanylate cyclase activity. The subcellular localization of guanylate cyclase will be determined with respect to its binding to f-actin under different lighting conditions. An actin cytoskeleton is also central to the structure of rhabdomeres. The ninaC proteins have a myosin-like domain and appear to associate with the actin cytoskeleton. Biochemical approaches are proposed to determine whether the proteins are indeed functional myosins. In addition, the photoreceptor ultrastructure of flies, with deletion and site-specific mutations in the ninaC gene, will be examined to help elucidate ninaC function. II. Calpain in rod outer segments. The aim of this section is to understand the regulation and function of calpain in rod outer segments. This calcium-activated neutral protease has been implicated in the organization of the rod outer segment actin cytoskeleton and in the regulation of rhodopsin. The calpain system in rod outer segments will be characterized better by identifying proteins that inhibit or activate the enzyme, proteins that bind (and thus help target) the enzyme to the cytoskeleton, and proteins that are in situ substrates. In particular, experiments will test whether any of the actin cytoskeletal elements are proteolysed by calpain in situ, and whether inhibition of calpain activity affects disk membrane morphogenesis. The selective proteolysis of arrestin by calpain will be studied further by identifying the sites of cleavage, the subcellular distribution of truncated arrestin, and the effects of this truncation on rhodopsin function.

这项研究的长期目标是了解结构和 光感受器细胞的光转移室的功能。这 建议的计划是研究肌动蛋白细胞骨架和钙蛋白酶系统 在这个隔间中。两者似乎都在感光器中起关键作用 结构和功能。生化和细胞生物学程序将 被使用。 I.光转导室中的肌动蛋白结合蛋白。 本节的目的是解决两个的调节和功能 肌动蛋白结合蛋白：一种来自哺乳动物杆外部段，另一个来自 来自果蝇横纹肌。在光感受器的外部段中 肌动蛋白〜细胞骨架在磁盘膜更新中起着至关重要的作用。它 似乎还提供了鸟苷酸环化酶的结合位点，因此 可能有助于调节细胞的恢复到其黑暗适应状态。 结合研究将用于确定结合的性质 在F-肌动蛋白和鸟苷酸环化酶之间及其对鸟苷酸盐的影响 环化酶活性。鸟苷酸环化酶的亚细胞定位将 根据不同的结合在不同 照明条件。肌动蛋白细胞骨架也是 横纹肌的结构。 NINAC蛋白具有类似肌球蛋白的结构域 并似乎与肌动蛋白细胞骨架相关。生化 提出了方法来确定蛋白质是否确实是 功能性肌球蛋白。另外，光感受器的超微结构 果蝇在NINAC基因中具有缺失和位点特异性突变，将 进行检查以帮助阐明NINAC功能。 ii。杆外段的钙蛋白酶。 本节的目的是了解 杆外段的钙蛋白酶。这种钙激活的中性蛋白酶 已经与杆外部肌动蛋白的组织有关 细胞骨架和视紫红质的调节。 钙蛋白酶系统 通过识别蛋白质，将更好地表征杆外段 抑制或激活酶，结合的蛋白质（因此有助于 靶标）酶的酶和细胞骨架的酶和原位的蛋白质 基材。特别是，实验将测试是否有任何肌动蛋白 细胞骨架元素是由钙蛋白酶原位蛋白质元素的，以及是否是 钙蛋白酶活性的抑制会影响磁盘膜形态发生。这 通过calpain对抑制蛋白的选择性蛋白水解将进一步研究 识别乳沟的位点，亚细胞分布 截短逮捕蛋白，以及这种截断对视紫红质的影响 功能。