Role of dMiro Signaling for Axonal Transport of Mitochondria

dMiro 信号传导在线粒体轴突运输中的作用

• 批准号: 7405416
• 负责人: KONRAD ERNST ZINSMAIER
• 金额: $ 29.79万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7405416
• 关键词: Acute; Adaptor Signaling Protein; Aging; Apoptosis; Axon; Axonal Transport; Binding; Biological Models; Cardiomyopathies; Cell Respiration; Cell membrane; Chromosome Pairing; Chronic; Condition; Consumption; Coupling; Dendrites; Development; Disease; Dominant-Negative Mutation; Drosophila genus; Dynein ATPase; EF Hand Motifs; EF-Hand Domain; Fractionation; Goals; Growth Cones; Guanosine Triphosphate Phosphohydrolases; Homeostasis; Image; In Situ; Individual; Intracellular Transport; Kinesin; Label; Life; Link; Malignant Neoplasms; Measures; Microtubules; Mitochondria; Mitochondrial Proteins; Molecular; Molecular Conformation; Motor; Motor Activity; Motor Neurons; Movement; Muscular Dystrophies; Nerve; Nerve Degeneration; Neurons; Neuropathy; Paraplegia; Pathway interactions; Phenotype; Physiological; Plastics; Plus End of the Microtubule; Presynaptic Terminals; Protein Overexpression; Proteins; Role; Signal Pathway; Signal Transduction; Site; Stress; Synapses; System; Temperature; Testing; Time; Work; base; concept; dynactin; in vivo; loss of function mutation; mitochondrial membrane; mutant; prevent; respiration regulation; response; rho; sensor; synaptic function; targeted delivery

DESCRIPTION (provided by applicant): Mitochondria are vital for aerobic respiration, the regulation of Ca2+ homeostasis, apoptosis, aging, and cancer. The intracellular distribution of mitochondria is adaptable to physiological stresses and changes in cellular activity. This plastic control is believed to be especially important in neurons where mitochondria are enriched at regions of intense energy consumption like synapses. Despite the significance of mitochondria for synaptic function, we still do not understand the molecular mechanisms controlling their delivery and targeting to synapses. A comprehensive understanding is urgently needed since abnormal mitochondrial transport, like abnormal mitochondrial function, is associated with various forms of muscular dystrophy, cardiomyopathy, neuropathy, paraplegia, and neurodegeneration. Our previous work suggests that the evolutionary conserved mitochondrial Rho-like GTPase Miro may act as a mitochondrial sensor that integrates intracellular signals to control long-distance transport of mitochondria. Specifically, loss of Drosophila Miro (dMiro) function prevents mitochondrial transport into axons and dendrites while gain of dMiro function leads to an abnormal accumulation of mitochondria at motor nerve terminals. Together, these results suggest dMiro may control anterograde axonal transport and the distribution of mitochondria to synaptic sites. To further test this hypothesis, we will take advantage of the model system Drosophila and genetically manipulate dMiro and other proteins of the mitochondrial transport machinery. Mutant effects on mitochondrial transport will be primarily examined in larval motor neurons, their axons and axon terminals by live imaging of GFP-tagged mitochondria to resolve the following key issues: Aim 1 will resolve whether dMiro promotes net-anterograde axonal transport by increasing the efficiency of microtubules (MT) plus end- or decreasing minus end-directed transport. Aim 2 will determine the role of dMiro's EF-hand Ca2+ binding domains for mitochondrial transport and/or the intracellular distribution of mitochondria. Aim 3 will test the molecular mechanisms by which dMiro may control mitochondrial transport. The proposed project is expected to reveal important molecular signaling mechanisms that regulate the long- distance transport of mitochondria and their use-dependent distribution into synaptic terminals. Uncovering these signaling pathways will significantly expand our understanding of basic mechanisms and accelerate the development of new concepts for detecting, treating, and/or preventing disorders that are caused by defective mitochondrial transport pathways and/or impaired mitochondrial function.

描述（由申请人提供）：线粒体对于有氧呼吸、Ca 2+稳态调节、细胞凋亡、衰老和癌症至关重要。线粒体的细胞内分布适应生理应激和细胞活性的变化。这种可塑性控制被认为在神经元中特别重要，在神经元中，线粒体在像突触这样的强烈能量消耗区域富集。尽管线粒体对突触功能具有重要意义，但我们仍然不了解控制其传递和靶向突触的分子机制。一个全面的了解是迫切需要的，因为异常的线粒体转运，如异常的线粒体功能，与各种形式的肌营养不良症，心肌病，神经病，截瘫，和神经变性。我们以前的工作表明，进化保守的线粒体Rho样GTdR Miro可能作为线粒体传感器，整合细胞内信号，控制线粒体的长距离运输。具体地，果蝇Miro（dMiro）功能的丧失阻止线粒体转运到轴突和树突中，而dMiro功能的获得导致线粒体在运动神经末梢处的异常积累。总之，这些结果表明dMiro可以控制顺行轴突运输和线粒体到突触部位的分布。为了进一步验证这一假设，我们将利用果蝇的模型系统和遗传操纵dMiro和其他蛋白质的线粒体运输机制。突变体对线粒体运输的影响将主要在幼虫运动神经元，其轴突和轴突终端通过GFP标记的线粒体的实时成像来研究，以解决以下关键问题：目的1将解决dMiro是否通过增加微管（MT）的效率来促进净顺行轴突运输加上末端导向运输或减少负末端导向运输。目的2将确定dMiro的EF手Ca 2+结合结构域的线粒体运输和/或线粒体的细胞内分布的作用。目的3将测试dMiro可能控制线粒体转运的分子机制。该项目有望揭示重要的分子信号机制，调节线粒体的长距离运输及其使用依赖性分布到突触末梢。揭示这些信号通路将大大扩展我们对基本机制的理解，并加速检测，治疗和/或预防由线粒体转运通路缺陷和/或线粒体功能受损引起的疾病的新概念的发展。