Elementary Events of Intracellular Calcium Signaling

描述（由申请人提供）：Ca2+从细胞内储存释放到细胞质中被用作几乎所有细胞类型的信号传导机制，以调节各种功能，如电兴奋性，分泌，增殖和细胞死亡。改进的成像技术显示，通过肌醇三磷酸受体/通道（IP3R）的Ca2+释放不连续发生，作为Ca2+信号的层次，涉及单个通道（“基本”事件）和多个通道（“基本”事件）的协调开放。这些短暂的、局部的游离[ca2 +]升高是通过IP3R聚集在内质网上离散的功能释放位点引起的。单个位点具有自主的信号功能，其活性可能通过Ca2+扩散和Ca2+诱导的Ca2+释放进一步协调，以传播全球细胞Ca2+波。因此，基本和基本事件形成了复杂时空Ca2+信号的分层构建块，允许细胞功能的分级和选择性调节。因此，阐明它们的产生、相互作用和功能后果对于理解无处不在的Ca2+信使通路的生理功能及其在病理状态中的参与至关重要。我们的总体目标是阐明细胞如何产生ip3介导的Ca2+信号的层次结构，这些信号如何用于效应反应的特定和局部调节，以及信号通路的中断如何参与疾病。通过利用先进的生物光子工具-包括共聚焦，多光子和全内反射显微镜，以及光释放IP3 -我们的目标是：(i)开发改进的光学技术，以便通过完整细胞内的单个通道成像Ca2+通量。（ii）阐明IP3R在释放位点的活性是如何被编排以产生基本的Ca2v信号的。（iii）确定细胞Ca2+缓冲如何调节释放位点之间的协调以产生全局Ca2+信号。（iv）探索ca2 +瞬态的时空模式编码特定和选择性细胞信号的原理。(v)研究IPa/Ca2+信使通路在神经元信号传导和阿尔茨海默病发病机制中的作用。

DESCRIPTION (provided by applicant): The liberation of Ca2+ from intracellular stores into the cytosol 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 imaging technology has revealed that Ca2+ liberation through inositol trisphosphate receptor/channels (IP3R) occurs discontinuously, as a hierarchy of Ca2+ signals involving single channels ('fundamental' events) and concerted openings of multiple channels ('elementary' events). These transient, localized free [Ca 2+] elevations arise through IP3R clustered at discrete functional release sites on the endoplasmic reticulum. Individual sites 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 pathological states. Our overall goals are to elucidate how cells generate the hierarchy of IP3-mediated Ca2+ signals, how these are utilized for specific and localized regulation of effector responses, and how disruptions in the signaling pathway may be involved in disease. By utilizing advanced biophotonic tools - including confocal, multiphoton and total internal reflection microscopy, and photoreleased IP3 - we aim to: (i) Develop improved optical techniques so as to image Ca2+ flux through individual channels within the intact cell. (ii) Elucidate how the activity of IP3R at a release site is orchestrated to generate elementary Ca2v signals. (iii) Determine how cellular Ca2+ buffers modulate the coordination between release sites to generate global Ca2+ signals. (iv) Explore the principles by which spatio-temporal patterning of Ca 2+ transients encodes specific and selective cell signals. (v) Investigate the roles of the IPa/Ca2+ messenger pathway in neuronal signaling and in the pathogenesis of AIzheimer's disease.