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：
10004663
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/10004663
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着长期的兴趣，这促使我们研究一个这样的肌动蛋白群体线粒体分裂的功能是线粒体正确分布所必需的，线粒体自噬、氧化应激反应以及对不同代谢底物的适应。线粒体裂变与主要神经退行性疾病的病理有关，包括动力蛋白家族 GTPase Drp1 是阿尔茨海默病、亨廷顿病、帕金森病和 ALS 的核心参与者。在线粒体裂变中，裂变位点寡聚并促进膜收缩。触发线粒体分裂的机制尚不清楚。我们发现肌动蛋白聚合。裂变位点在哺乳动物的 Drp1 募集和线粒体裂变中发挥着重要作用。这一发现来自于我们对内质网结合福尔明 INF2 的关注，它组装了这个通过这些研究，我们开发了用于成像的活细胞系统。高空间和时间分辨率下的线粒体裂变，这使我们能够定义顺序我们还建立了导致线粒体上 Drp1 寡聚化的事件。研究肌动蛋白与 Drp1、INF2 和其他裂变成分相互作用的生化系统这些发现将使裂变最终实现无细胞重建。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线粒体裂变。哺乳动物线粒体裂变的一种“类型”的详细信息（由钙离子载体刺激），以及随后利用这些知识来定义由其他刺激引起的裂变机制。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（这将表明完整的机制理解），并定义激活的信号输入 INF2 突变与两个人有因果关系。疾病：局灶性和节段性肾小球硬化症（一种肾脏疾病）和腓骨肌萎缩症因此，我们的工作影响基础细胞生物学和疾病。实验室的第二个重点是 formin FMNL3 的丝状伪足组装。本研究策略中未讨论，我们将在该 MIRA 中继续我们的丝状伪足工作。 INF2 研究、多年仔细的细胞和生化工作正在带来令人惊讶的发现，包括 1) 丝状伪足与细胞-细胞和细胞-基质粘附之间的联系，以及 2) FMNL3 在内体动力学中的作用我们的总体愿景是存在未被发现的肌动蛋白群体。短暂且低丰度的细丝，介导关键的细胞功能。在我的实验室中正在揭示这些肌动蛋白丝群体。