Linking actin cytoskeleton to membrane dynamics in mitochondrial fission

将肌动蛋白细胞骨架与线粒体裂变中的膜动力学联系起来

基本信息

批准号：
10245015
负责人：
HENRY N HIGGS
金额：
$ 76.19万
依托单位：
DARTMOUTH COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10245015
关键词：
Actins Adhesions Alzheimer&apos s Disease Biochemical Calcium Cell physiology Cells Cellular biology Charcot-Marie-Tooth Disease Cytoskeleton Defect Disease Dynamin Endoplasmic Reticulum Event Family Filament Filopodia Focal Segmental Glomerulosclerosis Goals Guanosine Triphosphate Phosphohydrolases Huntington Disease Ionophores Kidney Kidney Diseases Knowledge Laboratories Link Mammals Mediating Membrane Metabolic Microfilaments Minor Mitochondria Mutation Neurodegenerative Disorders Neuropathy Organelles Oxidative Stress Parkinson Disease Pathology Peripheral Nervous System Diseases Physiological Play Population Process Research Role Signal Transduction Site Stimulus System Vision Work base biological adaptation to stress constriction human disease imaging system interest novel polymerization reconstitution recruit temporal measurement

项目摘要

We have a long-standing interest in actin polymerization mechanisms, which has led us to investigate quantitatively minor populations of filaments with important cellular roles. One such actin population functions in mitochondrial fission. Mitochondrial fission is required for proper mitochondrial distribution, mitophagy, oxidative stress response, and adaptation to varying metabolic substrates. Defects in mitochondrial fission are linked to the pathology of major neurodegenerative diseases, including Alzheimer's, Huntington's, Parkinson's, and ALS. The dynamin family GTPase Drp1 is a central player in mitochondrial fission, oligomerizing at fission sites and promoting membrane constriction. Still, the mechanisms that trigger mitochondrial fission are murky. We have discovered that actin polymerization at fission sites plays a major role in Drp1 recruitment and mitochondrial fission in mammals. This finding came from our focus on an endoplasmic reticulum-bound formin, INF2, which assembles this filament population. Through these studies, we have developed live-cell systems for imaging mitochondrial fission at high spatial and temporal resolution, which have allowed us to define the order of events leading to Drp1 oligomerization on mitochondria. We have also established refined biochemical systems to study interaction of actin with Drp1, INF2 and other components of the fission process, which will enable eventual cell-free reconstitution of fission. These discoveries have fundamentally changed our view of mitochondrial fission. Our goal in the next five years is to define one “type” of mammalian mitochondrial fission in detail (stimulated by calcium ionophore), and subsequently to use this knowledge to define fission mechanisms induced by other stimuli. We have two longer-term goals: to reconstitute actin-mediated mitochondrial fission using purified components (which would indicate full mechanistic understanding), and to define the signaling in-puts that activate fission in specific physiological situations. Mutations in INF2 are causally linked to two human diseases: focal and segmental glomerulosclerosis (a kidney disease) and Charcot-Marie-Tooth disease (a peripheral neuropathy). Thus, our work impacts both fundamental cell biology and disease- based research. A second focus of the laboratory is filopodia assembly by the formin FMNL3. While not discussed in this Research Strategy, we will continue our filopodia work in this MIRA. Similar to our INF2 studies, years of careful cellular and biochemical work are leading to surprising discoveries, including 1) links between filopodia and both cell-cell and cell-substratum adhesion, and 2) a role for FMNL3 in endosomal dynamics. Our overall vision is that there are undiscovered populations of actin filaments, transient and of low abundance, which mediate key cellular functions. The combined studies in my laboratory are revealing these actin filament populations.

我们对肌动蛋白聚合机制有长期的兴趣，这使我们调查了具有重要细胞作用的细丝的数量较小。一个这样的肌动蛋白种群线粒体裂变的功能。正确的线粒体分布需要线粒体裂变，线粒体，氧化应激反应和对不同代谢底物的适应。缺陷线粒体裂变与主要神经退行性疾病的病理有关，包括阿尔茨海默氏症，亨廷顿，帕金森氏症和ALS。 Dynamin Family GTPase DRP1是中心玩家在线粒体裂变中，裂变位点的寡聚并促进膜收缩。仍然，触发线粒体裂变的机制是模糊的。我们发现肌动蛋白聚合在裂变位置在哺乳动物的DRP1募集和线粒体裂变中起着重要作用。这发现来自我们关注内质网构成的formin，Inf2，它组装了细丝种群。通过这些研究，我们开发了用于成像的活细胞系统高空间和临时分辨率的线粒体裂变，这使我们能够定义命令导致线粒体上DRP1低聚的事件。我们还建立了精致研究肌动蛋白与DRP1，INF2和裂变的其他成分的肌动蛋白相互作用的生化系统过程，这将使最终无细胞的裂变重构。这些发现有从根本上改变了我们对线粒体裂变的看法。我们未来五年的目标是定义详细的哺乳动物线粒体裂变的一种“类型”（由钙离子载体刺激）和随后使用这些知识来定义其他刺激引起的裂变机制。我们有两个长期目标：使用纯化的成分重建肌动蛋白介导的线粒体裂变（这将表明完全理解），并定义激活的信号传导在特定的身体情况下进行裂变。不幸的是，INF2中的突变与两个人有关疾病：局灶性和分段性肾小球硬化（一种肾脏疾病）和charcot-marie-tooth 疾病（周围神经病）。这，我们的工作影响了基本细胞生物学和疾病 - 基于研究。实验室的第二个重点是flmin fmnl3的丝状组件。尽管我们将在此研究策略中没有讨论，我们将继续在此Mira中继续进行丝状作品。类似于我们的 INF2研究，多年的仔细细胞和生化工作导致令人惊讶的发现，包括1）丝状菌与细胞 - 细胞和细胞 - 丝状粘合剂之间的联系，以及2）内体动力学中的FMNL3。我们的总体愿景是肌动蛋白未被发现细丝，瞬态和低丰度，介导关键细胞功能。合并研究在我的实验室中，揭示了这些肌动蛋白丝种群。