Molecular Mechanism of Mitochondrial Membrane Transport

线粒体膜运输的分子机制

• 批准号: 10396663
• 负责人: Liang Feng
• 金额: $ 41.96万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10396663
• 关键词: Address; Adopted; Affinity; Allosteric Regulation; Apoptosis; Architecture; Binding; Binding Sites; Biophysics; Calcium; Calorimetry; Cations; Cell Death; Cell Survival; Cells; Complex; Cryoelectron Microscopy; Crystallization; Disease; Epilepsy; Future; Gatekeeping; Heart failure; Homeostasis; Homologous Gene; Human; Ion Channel; Ions; Link; Mediating; Metabolic; Methods; Mitochondria; Molecular; Molecular Probes; Muscular Dystrophies; Mutation; N-terminal; Neurodegenerative Disorders; Neurons; Pathology; Physiological; Physiological Processes; Physiology; Play; Post-Translational Protein Processing; Process; Production; Property; Protein Isoforms; Proteins; Regulation; Reperfusion Injury; Resolution; Rest; Role; Route; Ruthenium Red; Shapes; Signal Transduction; Structure; Therapeutic; Time; Tissues; Titrations; Transmembrane Transport; Work; base; calcium uniporter; cell growth; design; excitotoxicity; experimental study; improved; inhibitor; insight; mitochondrial membrane; novel; novel therapeutics; prevent; response; therapeutic target; uptake

PROJECT SUMMARY Mitochondrial calcium (Ca2+) uptake is central to many fundamental physiological processes. It stimulates ATP production during times of increased metabolic need and provides a Ca2+ sink to modulate Ca2+-mediated signaling locally within a cell. Mitochondrial Ca2+ concentrations also regulate apoptosis and dysregulation–– specifically, Ca2+ overload––is a hallmark of pathologies ranging from neuronal excitotoxicity to heart failure and some epilepsies to muscular dystrophies. Yet despite the importance of mitochondrial Ca2+ uptake in normal physiology and disease, the molecular machinery mediating this process is relatively recently identified and many fundamental questions remain to be answered. The main route of Ca2+ influx to mitochondria is a channel called mitochondrial calcium uniporter, which includes the ubiquitous pore-forming subunit MCU and, depending on the species, several regulatory subunits (termed “uniplex” when in complex). This novel channel is highly selective for Ca2+, and its activity is tightly regulated by cytosolic Ca2+ concentration. My group recently determined a high-resolution crystal structure for a fungal MCU that defined a novel channel architecture and revealed a high-affinity Ca2+-binding site. Moreover, our cryo-EM structure of the human uniplex holocomplex revealed its architecture and hints at the mechanisms by which it is regulated. With these structures and the methods we developed, my lab is uniquely poised to embark on the mechanistic understanding of the mitochondrial calcium uniporter. Here, we propose to: 1) elucidate the structural and biophysical basis of ion selectivity, conduction and inhibition; 2) understand mechanisms of the channel gating and the long-range modulation; and 3) probe the molecular basis of Ca2+-dependent regulation of the uniplex. These results will give us much needed mechanistic insights into the activity and regulation of mitochondrial calcium uniporter, expanding our understanding of general principles of Ca2+ channels. In addition, they should provide a strong framework to aid the design of MCU inhibitors, which may represent promising treatments for diseases and pathologies marked by MCU dysregulation and mitochondrial Ca2+ overload. !

项目概要 线粒体钙 (Ca2+) 吸收是许多基本生理过程的核心。它刺激 ATP 在代谢需求增加时产生，并提供 Ca2+ 汇来调节 Ca2+ 介导的 细胞内局部信号传导。线粒体 Ca2+ 浓度也调节细胞凋亡和失调–– 具体来说，Ca2+超载是从神经元兴奋性毒性到心力衰竭等病理学的标志 有些癫痫会导致肌肉营养不良。然而，尽管线粒体 Ca2+ 摄取在正常情况下很重要， 生理学和疾病中，介导这一过程的分子机制是最近才被识别出来的，并且许多 基本问题仍有待回答。 Ca2+ 流入线粒体的主要途径是称为线粒体钙单向转运蛋白的通道，该通道 包括普遍存在的成孔亚基 MCU，以及根据物种不同还包括几个调节亚基 （在复合体中时称为“单工体”）。这种新型通道对 Ca2+ 具有高度选择性，并且其活性紧密 受细胞质 Ca2+ 浓度调节。 我的团队最近确定了真菌 MCU 的高分辨率晶体结构，该结构定义了一种新颖的 通道结构并揭示了高亲和力的 Ca2+ 结合位点。此外，我们的人体冷冻电镜结构 单链全复合体揭示了它的结构并暗示了它的调节机制。有了这些 结构和我们开发的方法，我的实验室独特地准备着手机械 了解线粒体钙单向转运蛋白。 在这里，我们建议：1）阐明离子选择性、传导性和离子选择性的结构和生物物理基础。 抑制; 2）了解通道门控和远程调制的机制； 3）探测 单链Ca2+依赖性调节的分子基础。 这些结果将为我们提供关于线粒体活性和调节的急需的机制见解。 钙单向转运蛋白，扩展了我们对 Ca2+ 通道一般原理的理解。此外，他们应该 提供了一个强大的框架来帮助设计 MCU 抑制剂，这可能代表了有前景的治疗方法 以 MCU 失调和线粒体 Ca2+ 超载为特征的疾病和病理。 ！