Molecular and physiological analysis of mitochondrial calcium uptake

线粒体钙摄取的分子和生理分析

• 批准号: 9036744
• 负责人: Julia Chang Liu
• 金额: --
• 依托单位: U.S. NATIONAL HEART LUNG AND BLOOD INST
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2018-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9036744
• 关键词: Affect; Animal Model; Animals; Ataxia; Autophagocytosis; Behavior; Binding Proteins; Biochemical; Bioenergetics; Biological; Biological Assay; Biological Models; Body Composition; Body Weight; CRISPR/Cas technology; Calcium; Cell Death; Cell Line; Cell physiology; Cells; Co-Immunoprecipitations; Complex; Confocal Microscopy; Cultured Cells; Disease; EF Hand Motifs; Embryo; Energy Metabolism; Exhibits; Fibroblasts; Functional disorder; Gatekeeping; Generations; Genetic; Genus Hippocampus; Health; Homeostasis; Human; Innovative Therapy; Knock-out; Knockout Mice; Lead; Learning Disorders; Link; Measurement; Measures; Membrane Proteins; Metabolism; Mitochondria; Mitochondrial Diseases; Mitochondrial Matrix; Modeling; Molecular; Molecular Weight; Mus; Myopathy; Names; Necrosis; Patients; Permeability; Phenocopy; Phenotype; Physiological; Physiology; Play; Production; Property; Proteins; Regulation; Resources; Respiration; Role; Signaling Molecule; Site; Stimulus; Structure; Swelling; Testing; Tissues; Tremor; VDAC1 gene; Wild Type Mouse; calcium uniporter; clinically relevant; extracellular; human disease; loss of function mutation; mitochondrial permeability transition pore; motor disorder; mouse model; mutant; paralogous gene; protein complex; public health relevance; response; uptake

 DESCRIPTION (provided by applicant): Popularly known as "the powerhouse of the cell," mitochondria are not only the site of metabolism and energy generation but also a hub for other cellular processes, including the initiation of cell death. Mitochondrial uptake of the signaling molecule calcium plays a role in the stimulation of ATP production, but too much calcium can lead to opening of the mitochondrial permeability transition pore (mPTP), triggering necrosis. The recent identification of the molecule forming the pore through which calcium can rapidly enter the mitochondria, the mitochondrial calcium uniporter (MCU), has provided a genetic means to directly test the functional importance of calcium uptake. In particular, MCU is part of a large multi-protein complex including other protein components. EMRE and MICU1 are two of these proteins that in cell lines have been shown to play critical roles in regulation of calcium uptake. EMRE was found to be necessary for MCU activity, and its deletion blocked calcium from entering mitochondria. Though its mechanism is controversial, MICU1 has been characterized as a gatekeeper of MCU, inhibiting MCU activity at low levels of extramitochondrial calcium and stimulating MCU when calcium levels rise. This project began with the generation of the first animal models of EMRE and MICU1 deletion. The aims of this project are to determine the impact of EMRE and MICU1 deletion on isolated mitochondria, on primary cells, and on the physiology of the whole animal. The new EMRE and MICU1 knockout mice also make it possible to determine the topology of the calcium uniporter complex, measure effects on basal bioenergetics, and elucidate the role of EMRE and MICU1 respectively in the regulation of mitochondrial calcium uptake and homeostasis. Furthermore, mouse models will reveal the consequences of mitochondrial calcium deregulation on cell death responses, physiological phenotypes including body weight and composition, and disease pathophysiology. Interestingly, human patients with loss-of-function mutations in MICU1 present with conditions such as proximal myopathy and extrapyramidal motor disorder. MICU1 knockout mice are preliminarily observed to exhibit ataxia and tremors, suggesting that this model may mirror human disease features and thus potentially motivate innovative therapies to treat mitochondrial disorder. Altogether, EMRE and MICU1 knockout mice are valuable resources for answering biological questions with both basic and clinical relevance.

 描述（由申请人提供）：线粒体俗称“细胞的动力室”，它不仅是新陈代谢和能量产生的场所，也是其他细胞过程的中心，包括细胞死亡信号传导的启动。钙分子在刺激 ATP 产生中发挥作用，但过多的钙会导致线粒体通透性转换孔 (mPTP) 打开，引发坏死。最近鉴定出形成该分子的分子。钙可以通过其快速进入线粒体的孔，即线粒体钙单向转运蛋白（MCU），它提供了一种直接测试钙吸收功能重要性的遗传方法。 EMRE 和 MICU1 是包含其他蛋白质成分的大型多蛋白质复合物，它们在细胞系中已被证明在调节钙吸收中发挥着关键作用，并且被发现对 MCU 活性是必需的，并且其缺失会阻碍钙的形成。尽管其机制存在争议，但 MICU1 被认为是 MCU 的看门人，在线粒体外钙水平较低时抑制 MCU 活性，并在钙水平升高时刺激 MCU。 该项目始于第一个 EMRE 和 MICU1 缺失的动物模型。该项目的目的是确定 EMRE 和 MICU1 缺失对分离的线粒体、原代细胞以及整个动物的生理学的影响。 EMRE 和 MICU1 敲除小鼠还可以确定钙单向转运蛋白复合物的拓扑结构，测量对基础生物能的影响，并分别阐明 EMRE 和 MICU1 在调节此外，小鼠模型将揭示线粒体钙失调对细胞死亡反应、包括体重和组成在内的生理表型以及疾病病理生理学的影响，提示 MICU1 存在功能丧失突变的人类患者。初步观察到近端肌病和锥体外系运动障碍等疾病的小鼠表现出共济失调和震颤，这表明该模型可能反映了人类疾病的特征，从而可能激发创新疗法的发展。总而言之，EMRE 和 MICU1 敲除小鼠是回答具有基础和临床意义的生物学问题的宝贵资源。