Mitochondrial Fusion and Division

线粒体融合与分裂

• 批准号: 7985893
• 负责人: Hiromi Sesaki
• 金额: $ 31.98万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7985893
• 关键词: Address; Affect; Alzheimer' s Disease; Autosomal Dominant Optic Atrophy; Axon; Binding; Binding Proteins; Biochemical; Biological Assay; Cell Shape; Cells; Cellular biology; Cerebellum; Charcot-Marie-Tooth Disease; Data; Dendrites; Development; Disease; Dynamin; Electron Microscopy; Embryo; Equilibrium; Event; Fibroblasts; GTP Binding; Guanosine Triphosphate; Guanosine Triphosphate Phosphohydrolases; Huntington Disease; Hydrolysis; Immunofluorescence Microscopy; Journals; Knockout Mice; Knowledge; Life; Liposomes; Mammals; Mediating; Membrane; Membrane Fusion; Membrane Proteins; Mitochondria; Molecular; Morphology; Mus; Nerve Degeneration; Neurites; Neurodegenerative Disorders; Neurons; Null Lymphocytes; Organelles; Outcome Study; Outer Mitochondrial Membrane; Parkinson Disease; Pathogenesis; Physiological; Principal Investigator; Process; Proteins; Purkinje Cells; Regulation; Research; Role; Set protein; Shapes; Structure; System; Testing; Translating; Yeasts; cellular imaging; granule cell; innovation; insight; mitochondrial membrane; nervous system disorder; novel; polarized cell; public health relevance; relating to nervous system; yeast protein

DESCRIPTION (provided by applicant): The mitochondrion is a dynamic membrane-bound organelle that undergoes fusion and division. The balance between these opposing events, which occur in a coordinated manner, is a key determinant of organelle size, number, and shape. Mitochondrial fusion and division are mediated by conserved dynamin-related GTPases including Mfn (mammals)/Fzo1p (yeast) for fusion and Drp1 (mammals)/Dnm1p (yeast) for division. Abnormalities in mitochondrial fusion and division are associated with many neurodegenerative diseases such as Charcot-Marie-Tooth neuropathy, dominant optic atrophy, Alzheimer's disease, Huntington's disease, and Parkinson's disease. Many of these diseases affect postmitotic neurons, which contain mitochondria along their long axons and branched dendrites. Understanding the pathogenesis of these diseases requires a deeper knowledge of the molecular mechanisms that mediate and coordinate mitochondrial fusion and division as well as the physiological functions of these events. The proposed research will uncover how mitochondria fuse (Aim 1), how mitochondrial fusion and mitochondrial division are coordinated (Aim 2), and how mitochondrial division controls mitochondrial distribution in postmitotic neurons (Aim 3). To study the molecular mechanisms underlying mitochondrial fusion in Aim 1, we have purified and biochemically characterized two yeast proteins that are required for mitochondrial fusion- Fzo1p GTPase and the Fzo1p- binding protein Ugo1p. Using these proteins, we have developed assays for GTP binding, GTP hydrolysis, and GTP-dependent membrane fusion. These novel assays will allow us to dissect the functions of Fzo1p GTPase and Ugo1p in mitochondrial fusion. In Aim 2, we will determine how mitochondrial fusion and division are coordinated. We have shown that the loss of Drp1 reduces Mfn1 and Mfn2 levels in Drp1-null mouse embryonic fibroblasts. We will determine how changes in Drp1 levels are translated into regulation of Mfn levels and mitochondrial fusion. In Aim 3, we will determine the physiological roles of mitochondrial division in neurons by deleting Drp1 from postmitotic neurons using the Cre-loxP system in mice. Preliminary data show that Drp1 loss induces alterations in mitochondrial distribution and neurodegeneration. We will determine how mitochondrial division controls organelle morphology and distribution in postmitotic neurons. Successful completion of the proposed studies will provide mechanistic insights into mitochondrial fusion, the coordination mechanism that balances mitochondrial fusion and division, and the physiological role of mitochondrial division in neurons. PUBLIC HEALTH RELEVANCE: Abnormalities in mitochondrial fusion and division are associated with many neurological disorders. To gain a better understanding of the pathogenesis of these diseases, we will investigate the molecular mechanisms and physiological functions of mitochondrial fusion and division.

描述（由申请人提供）：线粒体是一种动态的膜结合细胞器，会经历融合和分裂。这些以协调方式发生的对立事件之间的平衡是细胞器大小、数量和形状的关键决定因素。线粒体融合和分裂由保守的动力相关 GTP 酶介导，包括用于融合的 Mfn（哺乳动物）/Fzo1p（酵母）和用于分裂的 Drp1（哺乳动物）/Dnm1p（酵母）。线粒体融合和分裂的异常与许多神经退行性疾病有关，例如夏科-马里-图思神经病、显性视神经萎缩、阿尔茨海默病、亨廷顿病和帕金森病。其中许多疾病会影响有丝分裂后神经元，这些神经元的长轴突和分支树突上含有线粒体。了解这些疾病的发病机制需要更深入地了解介导和协调线粒体融合和分裂的分子机制以及这些事件的生理功能。拟议的研究将揭示线粒体如何融合（目标 1）、线粒体融合和线粒体分裂如何协调（目标 2）以及线粒体分裂如何控制有丝分裂后神经元中的线粒体分布（目标 3）。为了研究 Aim 1 中线粒体融合的分子机制，我们纯化了线粒体融合所需的两种酵母蛋白 - Fzo1p GTPase 和 Fzo1p 结合蛋白 Ugo1p，并对其进行了生化表征。使用这些蛋白质，我们开发了 GTP 结合、GTP 水解和 GTP 依赖性膜融合的检测方法。这些新颖的检测方法将使我们能够剖析 Fzo1p GTPase 和 Ugo1p 在线粒体融合中的功能。在目标 2 中，我们将确定线粒体融合和分裂如何协调。我们已经证明，Drp1 缺失会降低 Drp1 缺失小鼠胚胎成纤维细胞中 Mfn1 和 Mfn2 的水平。我们将确定 Drp1 水平的变化如何转化为 Mfn 水平和线粒体融合的调节。在目标 3 中，我们将使用小鼠体内的 Cre-loxP 系统从有丝分裂后神经元中删除 Drp1，从而确定神经元中线粒体分裂的生理作用。初步数据表明，Drp1 缺失会导致线粒体分布的改变和神经退行性变。我们将确定线粒体分裂如何控制有丝分裂后神经元的细胞器形态和分布。成功完成拟议的研究将为线粒体融合、平衡线粒体融合和分裂的协调机制以及线粒体分裂在神经元中的生理作用提供机制见解。 公共卫生相关性：线粒体融合和分裂的异常与许多神经系统疾病有关。为了更好地了解这些疾病的发病机制，我们将研究线粒体融合和分裂的分子机制和生理功能。