Molecular Mechanisms of Mitochondrial Ca2+ Transport

线粒体 Ca2 运输的分子机制

基本信息

批准号：
9000157
负责人：
Gyorgy Hajnoczky
金额：
$ 35.35万
依托单位：
THOMAS JEFFERSON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-02-01 至 2017-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9000157
关键词：
Affect Affinity Amino Acids Animal Model Binding Bioenergetics C-terminal Calcium Calcium Oscillations Calcium Signaling Cell Death Cell Respiration Cell Survival Cells Cellular Metabolic Process Cellular Stress Response Charge Complement Complex Development Disease Dominant-Negative Mutation Drug Targeting EF Hand Motifs EF-Hand Domain Employee Strikes Energy Metabolism Evolution Fasting Hepatic Hepatocyte Hereditary Disease Homeostasis Human Injection of therapeutic agent Injury Inner mitochondrial membrane Ischemia Knockout Mice Link Liver Measurement Mediating Methods Mitochondria Modeling Molecular Mouse Cell Line Mus Mutation Myopathy Nerve Degeneration Neurons Paper Pathway interactions Phenotype Physiological Physiology Protein Isoforms Proteins Publications Publishing Regulation Reperfusion Therapy Reporting Role Signal Transduction Site Stress System Testing Time Tissues VDAC1 gene Virus Work base calcium uniporter cell injury driving force feeding fluorescence imaging human disease in vivo new therapeutic target novel paralogous gene uptake

Affect Affinity Amino Acids Animal Model Binding Bioenergetics C-terminal Calcium Calcium Oscillations Calcium Signaling Cell Death Cell Respiration Cell Survival Cells Cellular Metabolic Process Cellular Stress Response Charge Complement Complex Development Disease Dominant-Negative Mutation Drug Targeting EF Hand Motifs EF-Hand Domain Employee Strikes Energy Metabolism Evolution Fasting Hepatic Hepatocyte Hereditary Disease Homeostasis Human Injection of therapeutic agent Injury Inner mitochondrial membrane Ischemia Knockout Mice Link Liver Measurement Mediating Methods Mitochondria Modeling Molecular Mouse Cell Line Mus Mutation Myopathy Nerve Degeneration Neurons Paper Pathway interactions Phenotype Physiological Physiology Protein Isoforms Proteins Publications Publishing Regulation Reperfusion Therapy Reporting Role Signal Transduction Site Stress System Testing Time Tissues VDAC1 gene Virus Work base calcium uniporter cell injury driving force feeding fluorescence imaging human disease in vivo new therapeutic target novel paralogous gene uptake

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项目摘要

Mitochondrial Ca2+ handling is central to cellular calcium homeostasis, energy metabolism and cell survival/cell death mechanisms. Impaired mitochondrial Ca2+ transport is also thought to be an important contributor in the development of a variety of diseases. After decades of frustrating ambiguity about the molecules mediating mitochondrial Ca2+ uptake, in 2010-2011, MICU1, an EF-hand domain protein, and MCU were identified as an indispensible regulator and pore forming component of the Ca2+ uniporter, respectively. Now, it is becoming possible to tackle the fundamental questions about the molecular mechanisms that underlie a sophisticated Ca2+ transport system and the physiological significance of MICU1, MCU and other uniporter components. We have started to investigate the mode of action of MICU1, and contrary to the first report, we found that MICU1 is not required to allow Ca2+ uptake through the uniporter but, instead, is critical to keep the uniporter closed at low cytoplasmic [Ca2+] ([Ca2+]c) concentrations and to support cooperative activation of the uniporter as the [Ca2+]c increases. These studies have been recently published in a widely recognized paper in Cell Metabolism. To further the study of the physiological significance of MICU1 we have generated a conditional MICU1 knockout mouse that has a striking phenotype and will provide several models for the proposed study. Our hypotheses are that (1) MICU1 employs its C-terminal cluster of positively charged amino acid residues to interact with the DIME domain of the intermembrane space loop of MCU, highlighting a site that might be a novel drug target, (2) MICU1 and MICU2 differently bind Ca2+ and/or Mg2+ with their EF-hands, providing a possible mechanisms for their distinct effects on the cooperative activation of the MCU, and (3) MICU1 is required in vivo for effective decoding of calcium signals in terms of oxidative metabolism in hepatocytes under fed and fasting conditions. To explore the role of MICU1 in Ca2+ handling we will apply advanced fluorescence imaging approaches, including some novel methods combined with assessment of cell bioenergetics and the activity of cell survival regulating pathways in the same models. The proposal relies on the use of a powerful targeting system of MICU1 in both cell lines and mouse tissues. The proposed work will uncover the mechanism of the sophisticated Ca2+- and time-dependent control of the uniporter and will expose MICU1's role in keeping mitochondria healthy and responsive to Ca2+.

线粒体Ca2+处理对于细胞钙稳态，能量代谢和细胞存活/细胞是核心死亡机制。线粒体CA2+运输受损也被认为是重要的贡献者各种疾病的发展。经过数十年的沮丧分子介导的歧义线粒体Ca2+摄取，2010- 2011年，MICU1，EF手域蛋白和MCU被鉴定为一个不可或缺的调节剂和孔形成Ca2+ Uniporter的成分。现在，它正在变得可以解决有关分子机制的基本问题 CA2+运输系统以及MICU1，MCU和其他Uniporter组件的生理意义。我们已经开始研究MICU1的作用方式，并与第一个报告相反，我们发现Micu1 不需要通过Uniporter允许Ca2+摄取，而是至关重要低细胞质[Ca2+]（[Ca2+] c）浓度，并支持单位的合作激活 [Ca2+] C增加。这些研究最近发表在细胞中广泛认可的论文中代谢。为了进一步研究MICU1的生理意义具有惊人表型的MICU1敲除小鼠，将为拟议的研究提供多种模型。我们的假设是（1）MICU1采用了带正电荷氨基酸残基的C末端簇与MCU的膜间空间循环的一角钱域进行交互，突出显示了一个可能是一个的位点新型药物靶标，（2）MICU1和MICU2不同地结合Ca2+和/或Mg2+的EF手，提供了A 它们对MCU合作激活的明显影响的可能机制，（3）MICU1是需要体内，以有效地解码钙信号在肝细胞中的氧化代谢方面美联储和禁食条件。为了探索MICU1在Ca2+处理中的作用，我们将应用高级荧光成像方法，包括一些新型方法与细胞评估结合生物能和细胞存活的活性调节相同模型中的途径。该提议依靠在细胞系和小鼠组织中使用强大的MICU1靶向系统。拟议的工作将发现复杂的Ca2+的机制，以及对Uniporter的时间依赖的控制，并将暴露 MICU1在保持线粒体健康和对Ca2+的反应方面的作用。