Mechanisms of Pulsatile Calcium Signaling

脉动钙信号传导机制

• 批准号: 7342490
• 负责人: Gyorgy Hajnoczky
• 金额: $ 30.38万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-20 至 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7342490
• 关键词: Buffers; Calcium; Calcium Signaling; Calcium Spikes; Calmodulin; Cell Death; Cell Survival; Cell membrane; Cell physiology; Cells; Communication; Condition; Coupling; Crosslinker; Cytoplasm; Data; Development; Down-Regulation; Elements; Endoplasmic Reticulum; Energy Metabolism; Evaluation; Event; Goals; Growth Factor; Hormones; ITPR1 gene; Image; Immunoelectron Microscopy; Ion Transport; Knockout Mice; Label; MYO5A gene; Measures; Mediating; Membrane; Membrane Transport Proteins; Metabolism; Methods; Microtubules; Mitochondria; Mitochondrial Proteins; Modeling; Molecular; Monitor; Movement; Mutation; Myosin ATPase; Myosin Type V; Numbers; Organelles; Outer Mitochondrial Membrane; Pathologic Processes; Physiological; Proteins; Range; Regulation; Research Personnel; Research Support; Role; Rough endoplasmic reticulum; Scheme; Shapes; Signal Transduction; Site; Small Interfering RNA; Structure; Testing; Time; VDAC1 gene; cell motility; fluorescence imaging; fluorophore; inositol-1,4,5-triphosphate receptor; knock-down; link protein; mutant; novel; novel strategies; programs; response; small molecule; spatial relationship; uptake

Cytoplasmic calcium spikes and oscillations elicited by a wide range of hormones and growth factors are propagated to the mitochondria to control several fundamental aspects of cell function including cell metabolism and survival. Delivery of the calcium signal to the mitochondria during short lasting Ca2+ release events is dependent on a local [Ca2+] regulation between IPs-activated endoplasmic reticulum (ER) Ca2+ release sites and mitochondrial Ca2+ uptake sites. This project aims at delineating the mechanisms that enable the local Ca2+ talk between ER and mitochondria. Our principal hypothesis is that the spatial relationship and calcium coupling between ER and mitochondria is controlled at several levels that include organellar motility, the ER-mitochondrial protein linkage and the function of the interacting channels. We propose that the motility of the organelles is controlled by Ca2+ to bring together ER and mitochondria at the sites of the ER Ca2+ mobilization. We postulate that the Ca2+-dependent regulation of motility is mediated by calmodulin and myosin V. We propose that at the sites of close associations of smooth or rough ER and mitochondria, protein links are formed to stabilize the interactions and to initiate a specialization in mitochondrial function. Furthermore, we suggest that at the ER-mitochondrial interface, both the IP3 receptor and the VDAC function is regulated, in part by Ca2+, to increase the efficacy of the Ca2* transfer to the mitochondria. As a major evidence for the local communication, our studies have shown that elementary calcium signals, calcium sparks propagate to the mitochondria giving rise to miniature, single mitochondrial calcium increases, referred as "calcium marks". Our data also indicated that mitochondrial calcium uptake contributes to the shaping of the elementary calcium signals in the cytoplasm. Furthermore, we have shown that the mitochondrial signal is more sensitive to suppression of Ca2+ release (IP3 receptor down-regulation, IP3 buffering and suboptimal ER Ca2* loading) than the cytoplasmic calcium signal. The studies have also revealed restriction of the Ca2+ transfer through the outer mitochondrial membrane and Ca2+-dependent facilitation of the Ca2+ uptake through the inner membrane. Furthermore, we have set up novel approaches for simultaneous evaluation of [Ca2+] and mitochondrial motility and described a Ca2+-dependent homeostatic control of mitochondrial movements. We will also introduce synthetic ER-mitochondrial crosslinkers and some novel multi-parameter fluorescence imaging methods to define the critical elements for the organization of the ER-mitochondrial Ca2+ coupling. Understanding the mechanisms of mitochondrial calcium signaling will provide a key component in elucidating the control of the fundamental mitochondrial contribution to cell survival and cell death in a wide range of physiological and pathological processes.

多种激素和生长因子引起的细胞质钙尖峰和振荡是 传播到线粒体以控制细胞功能的几个基本方面 代谢和生存。在短持久的Ca2+释放中，将钙信号传递到线粒体 事件取决于IPS激活的内质网（ER）Ca2+之间的局部[Ca2+]调节 释放位点和线粒体CA2+吸收位点。该项目旨在描述 启用ER和线粒体之间的局部CA2+谈话。 我们的主要假设是ER和ER之间的空间关系和钙耦合 线粒体在包括细胞器运动在内的多个级别受控 蛋白质连接和相互作用通道的功能。我们建议 细胞器由Ca2+控制，以将ER CA2+部位的ER和线粒体聚集在一起 动员。我们假设CA2+依赖性运动的调节是由钙调蛋白介导的 和肌球蛋白V。我们建议，在光滑或粗糙的ER的密切关联地点和 线粒体，蛋白质联系是为了稳定相互作用并启动专业化的蛋白质联系 线粒体功能。此外，我们建议在ER-Mitochrial接口，均IP3 受体和VDAC功能部分受CA2+的调节，以提高Ca2*的功效 转移到线粒体。 作为当地交流的主要证据，我们的研究表明，基本钙信号， 钙火花传播到线粒体产生微型，单线粒体钙 增加，称为“钙标记”。我们的数据还表明，线粒体钙摄取有助于 到细胞质中基本钙信号的形状。此外，我们已经证明了 线粒体信号对Ca2+释放的抑制更敏感（IP3受体下调，IP3 与细胞质钙信号相比，缓冲和次优的ER CA2*加载。研究也 揭示了通过线粒体外膜和Ca2+依赖性的CA2+转移的限制 通过内膜促进Ca2+摄取。此外，我们已经建立了新颖的方法 用于同时评估[Ca2+]和线粒体运动，并描述了CA2+依赖性稳态 线粒体运动的控制。我们还将介绍合成的ER-线粒体交联和 一些新型的多参数荧光成像方法，以定义 ER-线粒体Ca2+耦合的组织。了解线粒体钙的机制 信号传导将提供阐明基本线粒体控制的关键组成部分 在广泛的生理和病理过程中对细胞存活和细胞死亡的贡献。