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.

家长奖摘要 线粒体裂变对于线粒体的适当分布、线粒体自噬和氧化应激至关重要 反应和对不同代谢底物的适应缺陷与线粒体裂变有关。 主要神经退行性疾病的病理学，包括阿尔茨海默病、亨廷顿病、帕金森病、 动力蛋白家族 GTPase Drp1 是线粒体裂变的核心参与者，寡聚化。 裂变位点和促进膜收缩仍然是触发线粒体的机制。 我们发现裂变位点的肌动蛋白聚合在其中起着重要作用。 这一发现源于我们对哺乳动物中 Drp1 募集和线粒体裂变的长期兴趣。 通过福尔明蛋白进行肌动蛋白聚合，特别关注内质网结合 通过这些研究，我们开发了用于线粒体成像的活细胞系统。 高空间和时间分辨率的裂变，这使我们能够定义主要事件的顺序 我们还建立了精细的生化系统来研究线粒体上的 Drp1 寡聚化。 肌动蛋白与 Drp1、INF2 和裂变过程的其他成分的相互作用，这将使 这些发现从根本上改变了我们对裂变的无细胞重建的看法。 我们未来五年的目标是定义哺乳动物线粒体的一种“类型”。 详细裂变（由钙离子载体刺激），然后使用这些知识来定义 我们有两个长期目标：重建肌动蛋白。 使用纯化的成分介导线粒体裂变（这表明完整的机制 理解），并定义在特定生理情况下激活裂变的信号输入。 INF2 突变与两种人类疾病有因果关系：局灶性和节段性肾小球硬化症 （一种肾脏疾病）和腓骨肌萎缩症（一种周围神经病）因此，我们的工作会产生影响。 实验室的第二个重点是丝状伪足。 虽然本研究策略中没有讨论，但我们将继续我们的研究。 与我们的 INF2 研究类似，需要多年仔细的细胞和生化工作。 带来了令人惊讶的发现，包括 1) 丝状伪足与细胞-细胞和细胞-细胞之间的联系 基质粘附，2) FMNL3 在内体动力学中的作用。 是尚未发现的肌动蛋白丝群体，短暂且丰度低，介导关键 我实验室的综合研究揭示了这些肌动蛋白丝群体。