Mechanisms of Mitochondrial Distribution

线粒体分布机制

基本信息

批准号：
7896649
负责人：
Janet M. Shaw
金额：
$ 28.31万
依托单位：
UNIVERSITY OF UTAH
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-08-01 至 2012-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7896649
关键词：
Actins Adaptor Signaling Protein Address Apoptosis Binding Cardiomyopathies Cell Cycle Cell Death Cells Complex Cultured Cells Cytoplasm Defect Disease EF Hand Motifs Embryo Endoplasmic Reticulum Eukaryotic Cell Event Foundations Future Genetic Genetic Screening Griscelli Syndrome Guanosine Triphosphate Phosphohydrolases Health Homologous Gene Human Human Development Immunologic Deficiency Syndromes Investigation Kinesin Laboratories Lead Learning Lesion Link MYO5A gene Mediating Microfilaments Microtubules Mitochondria Mitochondrial Inheritance Mitochondrial Membrane Protein Modeling Molecular Morphology Motor Movement Muscular Dystrophies Myosin ATPase Myosin Light Chains Myosin Type V Nerve Degeneration Neurologic Neurons Organelles Outer Mitochondrial Membrane Paraplegia Pathway interactions Patients Peripheral Pigmentation physiologic function Process Proteins Regulation Research Personnel Saccharomyces cerevisiae Saccharomycetales Scientist Tail Testing Tissues Walking Yeasts base daughter cell design fly in vivo interest man mitochondrial membrane mutant novel public health relevance rab GTP-Binding Proteins receptor research study role model

项目摘要

DESCRIPTION (provided by applicant): In eukaryotic cells, mitochondrial movement or `transport' occurs by attaching the organelle to kinesin or myosin motor proteins that walk along microtubules or actin filaments, respectively. These mitochondrial transport events are required to distribute mitochondria within the cytoplasm and are also essential for inheritance of mitochondria by daughter cells during division. A molecular understanding of mitochondrial transport mechanisms is critical for human health, as genetic lesions that compromise mitochondrial distribution are linked to a growing list of human disorders, including some forms of muscular dystrophy, cardiomyopathy, paraplegia, and neurodegeneration. The basic mechanisms regulating mitochondrial transport are conserved from yeast to man. This proposal focuses on the molecules and machineries that mediate actin-based mitochondrial transport during division in the budding yeast, S. cerevisiae. Defects in yeast mitochondrial transport interfere with mitochondrial inheritance by daughter cells (buds). Previous studies identified two independent pathways that regulate yeast mitochondrial inheritance. The first pathway utilizes a peripheral mitochondrial adaptor protein called Mmr1. Mmr1 forms a complex with Myo2, a class V myosin motor protein. Experiments in this application will test the model that changes in Mmr1 abundance, activity and/or localization coordinate Mmr1-mediated mitochondrial inheritance with the cell cycle. The second mitochondrial inheritance pathway requires an endoplasmic reticulum (ER)- localized Rab GTPase called Ypt11. Ypt11 also forms a complex with Myo2. How an ER-anchored Rab controls inheritance of mitochondrial membranes is not understood. In this application, two alternative models to explain how ER-localized Ypt11 influences mitochondrial inheritance are proposed and tested. The principle investigator's laboratory recently described a third pathway required for mitochondrial inheritance. This pathway utilizes Gem1/Miro, a tail-anchored outer mitochondrial membrane protein containing two GTPase domains and two Ca2+binding EF-hand motifs. Gem1/Miro is conserved from yeast to man. Expression of mutant Miro in cultured cells leads to apoptosis, and flies with defective Gem1/Miro display neuronal defects. Experiments are proposed to determine whether Gem1/Miro acts via Myo2 and to identify specific effectors of its GTPase domains. Finally, the principle investigator's laboratory will study novel components of mitochondrial inheritance pathways identified in genetic screens. These studies will likely identify mammalian homologs that will allow future investigation of mitochondrial distribution mechanisms in human cells and tissues. Public Health Relevance: The studies outlined will advance the understanding of actin-based mitochondrial transport mechanisms. The results will be relevant to human development and health, as several of the molecules of interest have human homologs, including Myo2 (human myosin Va) and Gem1 (human Miro1 and Miro2). Defects in human myosin Va cause embryonic lethality, and patients with reduced myosin Va function suffer from Griscelli's syndrome, an often fatal disorder characterized by immunodeficiency, and neurological and pigmentation defects. Expression of mutant mammalian Miro alters mitochondrial morphology and induce cell death in cultured cells, and defects in fly Miro disrupt axonal mitochondrial transport, a function that is likely conserved in humans. Some of the proposed experiments may lead to the identification of homologs that control actin-based mitochondrial distribution processes in human cells and tissues. What is learned in the process may allow scientists and clinicians to manipulate the activities of these molecules for the benefit of human health.

描述（由申请人提供）：在真核细胞中，通过将细胞器连接到分别沿着微管或肌动蛋白丝的驱动蛋白或肌球蛋白运动蛋白上，即可进行线粒体运动或“传输”。这些线粒体转运事件需要在细胞质内分布线粒体，对于分裂过程中子细胞的线粒体遗传也是必不可少的。对线粒体转运机制的分子理解对于人类健康至关重要，因为损害线粒体分布的遗传病变与越来越多的人类疾病列表有关，包括某些形式的肌肉营养不良，心肌病，副骨，肢体疾病，副乳腺癌和神经化学因素。调节线粒体转运的基本机制是从酵母到人的保守的。该提案的重点是介导基于肌动蛋白的线粒体运输的分子和机械，在发芽的酵母中，酿酒酵母。酵母线粒体转运的缺陷干扰子细胞的线粒体遗传（芽）。先前的研究确定了调节酵母线粒体遗传的两种独立途径。第一个途径利用了称为MMR1的外周线粒体适配器蛋白。 MMR1与Myo2（肌蛋白蛋白v级）形成复合物。本应用程序中的实验将测试MMR1丰度，活性和/或定位坐标MMR1介导的线粒体遗传与细胞周期的模型。第二个线粒体遗传途径需要一个称为YPT11的内质网（ER） - 局部RAB GTPase。 YPT11还与Myo2形成了复杂的复合体。尚不清楚如何了解线粒体膜的ER锚定RAB的遗传。在此应用中，提出并测试了两个替代模型，以解释ER定位的YPT11如何影响线粒体遗传。主要研究者的实验室最近描述了线粒体遗传所需的第三条途径。该途径利用GEM1/Miro，这是一种尾部锚定的外部线粒体膜蛋白，其中包含两个GTPase域和两个Ca2+结合EF Hand基序。 Gem1/Miro从酵母到人都是保守的。培养细胞中突变体的表达会导致凋亡，而苍蝇的GEM1/miro则表现出神经元缺陷。提出了实验，以确定GEM1/MiRO是否通过MyO2起作用并确定其GTPase域的特定效应子。最后，原则研究者的实验室将研究在遗传筛选中确定的线粒体遗传途径的新成分。这些研究可能会鉴定出哺乳动物的同源物，从而将来可以研究人类细胞和组织中的线粒体分布机制。公共卫生相关性：概述的研究将提高对基于肌动蛋白的线粒体运输机制的理解。结果将与人类的发展和健康有关，因为一些感兴趣的分子具有人类同源物，包括肌2（人肌球蛋白VA）和GEM1（人Miro1和Miro2）。人肌球蛋白VA的缺陷会导致胚胎致死性，并且肌球蛋白VA功能降低的患者患有Griscelli综合征，这种致命性疾病通常具有免疫缺陷，神经和色素沉着缺陷。突变哺乳动物米罗的表达改变了线粒体的形态并诱导培养细胞中的细胞死亡，并在蝇中的缺陷破坏了轴突线粒体转运，这一功能可能在人类中是保守的。一些提出的实验可能导致鉴定人类细胞和组织中基于肌动蛋白的线粒体分布过程的同源物。在此过程中所学的知识可能允许科学家和临床医生操纵这些分子的活动，以使人类健康受益。