Supplement - Linking actin cytoskeleton to membrane dynamics in mitochondrial fission

补充-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

• 批准号: 10387000
• 负责人: HENRY N HIGGS
• 金额: $ 5.34万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 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/10387000
• 关键词: Actins; Adhesions; Alzheimer' s Disease; Award; Biochemical; Calcium; Cell physiology; Cells; Cellular biology; Charcot-Marie-Tooth Disease; Cytoskeleton; Defect; Disease; Dynamin; Endoplasmic Reticulum; Event; Family; Filopodia; Focal Segmental Glomerulosclerosis; Goals; Guanosine Triphosphate Phosphohydrolases; Homeostasis; Huntington Disease; Ionophores; Kidney Diseases; Knowledge; Laboratories; Link; Mammals; Mediating; Membrane; Metabolic; Microfilaments; Mitochondria; Mutation; Neurodegenerative Disorders; Organelles; Oxidative Stress; Parents; Parkinson Disease; Pathology; Peripheral Nervous System Diseases; Physiological; Play; Population; Process; Proteins; 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

Abstract of Parent Award Mitochondrial fission is essential 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 long-term interest in actin polymerization through formin proteins, with particular focus on an endoplasmic reticulum-bound formin, INF2. 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.

父母摘要 线粒体裂变对于正确的线粒体分布，线粒体，氧化应激至关重要 反应，并适应不同的代谢底物。线粒体裂变的缺陷与 主要神经退行性疾病的病理学，包括阿尔茨海默氏症，亨廷顿，帕金森氏症， 和ALS。 Dynamin家族GTPase DRP1是线粒体裂变的核心参与者，在 裂变部位并促进膜收缩。不过，触发线粒体的机制 裂变是模糊的。我们发现，裂变部位的肌动蛋白聚合在 哺乳动物中的DRP1募集和线粒体裂变。这一发现来自我们对 肌动蛋白聚合通过甲蛋白蛋白，特别关注内质网络结合 formin，inf2。通过这些研究，我们开发了用于成像线粒体的活细胞系统 高空间和临时分辨率的裂变，这使我们能够定义领先事件的顺序 在线粒体上进行DRP1低聚。我们还建立了精制的生化系统来研究 肌动蛋白与DRP1，INF2和裂变过程的其他成分的相互作用，这将启用 最终无细胞的裂变重构。这些发现从根本上改变了我们对 线粒体裂变。我们未来五年的目标是定义一种“类型”的哺乳动物线粒体 详细裂变（由钙离子载体刺激），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：重新建立肌动蛋白 - 使用纯化的成分介导的线粒体裂变（这将表明完全机械 理解），并定义在特定物理情况下激活裂变的信号传导。 不幸的是，INF2中的突变与两种人类疾病有关：局灶性和节段性肾小球硬化症 （一种肾脏疾病）和charcot-marie-tooth病（周围神经病）。那，我们的工作会影响 基本细胞生物学和基于疾病的研究。实验室的第二个重点是丝状 组装由Formin fmnl3组装。虽然没有在此研究策略中讨论，但我们将继续我们的 丝状在这个mira中起作用。与我们的INF2研究类似，多年的细胞和生化工作 导致令人惊讶的发现，包括1）丝状和细胞 - 细胞和细胞之间的联系 基质粘附和2）FMNL3在内体动力学中的作用。我们的整体愿景是那里 是未发现的肌动蛋白丝，瞬态和低丰度的种群，这会介导关键 细胞功能。我实验室的合并研究揭示了这些肌动蛋白丝种群。