Elementary Events of Intracellular Calcium Signaling

细胞内钙信号传导的基本事件

• 批准号: 8537203
• 负责人: IAN PARKER
• 金额: $ 46.68万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-08-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8537203
• 关键词: Address; Alzheimer' s Disease; Amyloid; Architecture; Biophotonics; Calcium; Calcium Oscillations; Calcium Signaling; Cell Death; Cell membrane; Cell physiology; Cells; Cessation of life; Complex; Computer software; Custom; Cytosol; Data; Detection; Diffusion; Disease; Dyes; Endoplasmic Reticulum; Event; Extracellular Fluid; Feedback; Gated Ion Channel; Generations; Goals; Heart failure; Image; Image Analysis; Imagery; Imaging Techniques; Imaging technology; Individual; Inositol; Ion Channel Gating; Ions; Kinetics; Label; Lasers; Lead; Life; Maps; Mediating; Membrane; Microscopy; Monitor; Movement; Noise; Optics; Pathogenesis; Pathway interactions; Pattern; Peptides; Photobleaching; Physiological; Plasma; Play; Population; Predisposition; Prions; Process; Property; Proteins; Receptor Signaling; Recruitment Activity; Regulation; Resolution; Role; Second Messenger Systems; Signal Pathway; Signal Transduction; Site; Spatial Distribution; Specificity; Spottings; Synaptic Transmission; Techniques; Technology; Time; Writing; amyloid peptide; base; brain cell; cell motility; cell type; improved; millisecond; monomer; nano; nanometer; neuronal cell body; novel; optical imaging; photolysis; polyglutamine; receptor; release of sequestered calcium ion into cytoplasm; second messenger; single molecule; spatiotemporal; stoichiometry; technique development; tool

DESCRIPTION (provided by applicant): The entry of Ca2+ ions into the cytosol from the extracellular fluid and from endoplasmic reticulum (ER) stores is used as a signaling mechanism by virtually all cell types to regulate functions as diverse as electrical excitability, secretion, proliferation and cell death. Improved optical technology now enables visualization of a hierarchy of Ca2+ signaling events, ranging from openings of single-channel Ca2+-permeable channels ('fundamental' events), concerted openings of clustered channels ('elementary' events) and propagating Ca2+ waves. The localized free [Ca2+] elevations arising through individual and clustered channels serve autonomous signaling functions, and their activity may further be coordinated through Ca2+ diffusion and Ca2+-induced Ca2+ release to propagate global cellular Ca2+ waves. Fundamental and elementary events thus form hierarchical building blocks underlying the complex spatiotemporal Ca2+ signals that permit graded and selective regulation of cell functions. Elucidation of their generation, interaction and functional consequences is, therefore, pivotal to understand the physiological functioning of the ubiquitous Ca2+ messenger pathway and its involvement in disease. Our overall goal is to elucidate, at the single-channel level, how cells generate the hierarchy of Ca2+ signals and how disruptions in Ca2+ signaling may be involved in disease pathogenesis. We focus on physiological Ca2+ signals generated by the ubiquitous inositol trisphosphate second messenger pathway, and on the pathogenic Ca2+-permeable pores formed by amyloid oligomers implicated in Alzheimer's disease. By utilizing novel biophotonic tools that now enable the optical imaging of calcium flux through individual channels and the localization and tracking of channel proteins with nanometer precision we aim to: (i) Further refine optical and analytical techniques for simultaneously monitoring Ca2+ flux through hundreds of individual channels in the plasma membrane and ER of intact cells. (ii) Elucidate how the activity of individual IP3 receptors (IP3R) at a release site is orchestrated to generate elementary Ca2+ puffs. (iii) Employ superresolution imaging techniques to determine the nanoscopic spatial distribution of IP3R, and how this impacts their functioning. (iv) Simultaneously monitor Ca2+ flux and peptide stoichiometry of individual amyloid pores to study fundamental mechanisms of membrane incorporation, channel gating and ion permeation.

描述(申请人提供)：钙离子从胞外液和内质网(ER)库进入胞浆是几乎所有类型的细胞都使用的一种信号机制，以调节各种功能，如电兴奋、分泌、增殖和细胞死亡。改进的光学技术现在可以可视化钙离子信号事件的层次结构，范围从单通道钙渗透通道的开口(基本事件)、集群通道的协调开口(基本事件)和传播钙波。通过单个和集群通道产生的局部游离[Ca~(2+)]升高具有自主信号功能，它们的活性可能通过Ca~(2+)扩散和Ca~(2+)诱导的Ca~(2+)释放来进一步协调，从而传播细胞内整体的Ca~(2+)波。因此，基础和基本事件形成了复杂的时空钙信号下的分层构建块，允许分级和选择性地调节细胞功能。因此，阐明它们的产生、相互作用和功能后果对于理解普遍存在的钙信使途径的生理功能及其在疾病中的参与至关重要。我们的总体目标是在单通道水平上阐明细胞如何产生钙信号的层次结构，以及钙信号的中断如何参与疾病的发病机制。我们的重点是由普遍存在的肌醇三磷酸第二信使途径产生的生理钙信号，以及与阿尔茨海默病有关的淀粉样寡聚体形成的致病的钙渗透孔。通过利用新的生物光子学工具，现在能够以纳米精度对单个通道的钙离子通量进行光学成像，并对通道蛋白进行定位和跟踪，我们的目标是：(I)进一步完善光学和分析技术，以同时监测完整细胞质膜和内质网中数百个单独通道的钙离子通量。(Ii)阐明单个IP3受体(IP3R)在释放部位的活性是如何被协调以产生基本的钙离子喷发的。(3)利用超分辨率成像技术确定IP3R的纳米空间分布，以及这如何影响其功能。(Iv)同时监测单个淀粉样毛孔的钙离子通量和多肽化学计量比，以研究膜掺入、通道门控和离子渗透的基本机制。