Regulation of TRP channels and visual transduction

TRP 通道和视觉转导的调节

• 批准号: 8655274
• 负责人: CRAIG MONTELL
• 金额: $ 30.98万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA BARBARA
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-01-01 至 2017-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8655274
• 关键词: Address; Affect; Arrestins; Autosomal Dominant Polycystic Kidney; Biochemical; Biological Models; Calcium; Calmodulin; Cells; Cellular biology; Complex; Couples; Cyclic GMP; Defect; Disease; Drosophila genus; Drosophila melanogaster; Electrophysiology (science); Event; Family; Fostering; Ganglioside Sialidase Deficiency Disease; Genes; Genetic; Goals; Heterotrimeric GTP-Binding Proteins; Human; Hydrolysis; In Vitro; Kidney Diseases; Light; Mechanics; Mediating; Mental Retardation; Modeling; Molecular; Monomeric GTP-Binding Proteins; Movement; Mus; Mutation; Natural regeneration; Nerve Degeneration; Neurodegenerative Disorders; Organism; Pathway interactions; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phospholipase C; Phospholipase D; Photoreceptors; Phototransduction; Protein Family; Proteins; Pupil light reflex; Regulation; Research; Retinal; Retinal Degeneration; Retinal Ganglion Cells; Rhodopsin; Role; Second Messenger Systems; Sensory; Signal Transduction; Sodium; Stimulus; System; TRP channel; Taste Perception; Temperature; Testing; Vertebrate Photoreceptors; Vision; Work; computerized data processing; design; disease-causing mutation; driving behavior; drug testing; fly; genetic regulatory protein; human disease; in vivo; in vivo Model; interest; overexpression; prevent; research study; second messenger

The long-term goal of our research is to understand the mechanisms underlying phototransduction in the fruitfly, Drosophila melanogaster. Drosophila phototransduction functions through a phospholipase C (PLC)- dependent signaling system, and culminates in Ca2+ and Na+ influx, via TRP channels. It is now clear that there exists a large family of mammalian TRP channels, many of which participate in a diversity of sensory signaling processes. The over-riding theme of this proposal is that phosphoinositide (PI) signaling is critical for regulatory events in Drosophila photoreceptor cells, which are more complex and varied than the established concept of gating the TRP channels through hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2). Experiments in this proposal are designed to challenge the current view that the only effector pathway for light-activated rhodopsin is a heterotrimeric G-protein/PLC pathway. Rather, we propose to test the idea that light activated rhodopsin also couples to a small GTPase, which in turn stimulates a phospholipase D (PLD), and the small GTPase and PLD are required for the light-dependent translocation of the rhodopsin regulatory protein, arrestin. We also propose to test the idea that PIs have an additional role in vivo, namely to regulate the TRP channel by preventing its interaction with inhibitory calcium/calmodulin. As part of a long-term goal to define the proteins that participate in PI signaling in photoreceptor cells, we propose to address the functional requirement for a type of PI-transfer protein that is conserved from flies to humans, but has not been characterized in any organism. To address these questions, we propose to employ a combination of genetics, electrophysiology, cell biology, germline transformation and biochemical approaches. Finally, to generalize from our work on fly vision to mammalian phototransduction, experiments are proposed to provide genetic evidence for a requirement for PI signaling in the intrinsically photosensitive retinal ganglion cells (ipRGCs) of the mouse, which function in the pupillary light reflex and several accessory light-driven behaviors. To study the regulation of TRP channels and phototransduction by PIs, we propose to test the hypotheses that: 1) light-dependent movement of Arrestin functions through a small GTPase and PLD-dependent pathway, 2) Drosophila TRP undergoes dual regulation by PIP3 and Ca2+/calmodulin in vivo, 3) a new PI-transfer protein is required for the Drosophila photoresponse, and 4) a mouse PI-transfer protein is required for function of the ipRGCs. During the last few years, four human diseases have been shown to be due to mutations in TRP channels, including the most common disease due to mutation in a single gene, autosomal dominant polycystic kidney disease, and mucolipidosis type IV, which causes severe neurodegeneration, mental retardation and retinal degeneration. Given that the molecular mechanisms underlying the activation of these human TRPs are poorly understood, Drosophila TRP provides an in vivo model for defining the mechanisms regulating TRP channels.

我们研究的长期目标是了解光转导的机制 果蝇，果蝇Melanogaster。果蝇通过磷脂酶C（PLC） - 依赖信号系统，并通过TRP通道在Ca2+和Na+流入中达到顶点。现在很明显 存在着大量的哺乳动物TRP渠道，其中许多参与了多样的感官 信号过程。该提案的过度骑行主题是磷酸肌醇（PI）信号至关重要 用于果蝇感光细胞中的调节事件，比与 通过磷脂酰肌醇4,5-双磷酸盐的水解进行门控TRP通道的建立概念 （PIP2）。本提案中的实验旨在挑战当前观点，即唯一的效应器 光活化的视紫红质的途径是一种异三聚体G蛋白/PLC途径。相反，我们建议测试 光激活视紫红质也将其伴随到一个小的GTPase的想法，从而刺激了A 磷脂酶D（PLD）以及小的GTPase和PLD是必需的 Rhodopsin调节蛋白，逮捕蛋白。我们还建议测试PI具有额外角色的想法 在体内，即通过防止其与抑制性钙/钙调蛋白的相互作用来调节TRP通道。 作为定义参与PI受体细胞PI信号的蛋白质的长期目标的一部分，我们 建议解决一种从果蝇到保守的PI转移蛋白的功能要求 人类，但在任何生物体中都没有被描述。为了解决这些问题，我们建议 结合遗传学，电生理学，细胞生物学，种系转化和生化 方法。最后，要从我们在蝇视觉上的工作概括到哺乳动物的光转导，实验 提议提供遗传证据，以便在本质上具有光敏性的PI信号传导要求 小鼠的视网膜神经节细胞（IPRGC），在瞳孔光反射中起作用，几个 配件轻驱动行为。为了研究PIS的TRP通道和光转导的调节，我们 提议测试以下假设：1）通过小的光动作的光依赖性运动 GTPase和PLD依赖性途径，2）果蝇TRP通过PIP3和 Ca2+/钙调蛋白在体内，3）果蝇光响应需要一种新的pi转移蛋白，4）a IPRGC功能所需的小鼠Pi转移蛋白是必需的。在过去的几年中，四个人 疾病已被证明是由于TRP通道中的突变，包括最常见的疾病 由于单个基因的突变，常染色体显性多囊性肾脏疾病和IV型粘脂质病 导致严重的神经退行性，智力低下和视网膜变性。鉴于那个 这些人类TRP激活的分子机制知之甚少，果蝇 TRP提供了一个体内模型，用于定义调节TRP通道的机制。