Mammalian iron-sulfur cluster biogenesis

哺乳动物铁硫簇生物发生

基本信息

批准号：
9550385
负责人：
TRACEY A. ROUAULT
金额：
$ 85.2万
依托单位：
EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/9550385
关键词：
Aconitate Hydratase Apoproteins Biogenesis Biological Markers Cell Nucleus Cells Cessation of life Citric Acid Cycle Collaborations Complex Cytosol Data Disease Enzymes FGF21 gene Ferredoxin Fibroblasts Friedreich Ataxia Genes Genetic Transcription Goals Hereditary Disease Homeostasis Infant Iron Iron Overload Iron-Sulfur Proteins Lactic Acidosis Mammalian Cell Mediating Mitochondria Mitochondrial Diseases Molecular Chaperones Mutagenesis Mutation Myopathy Neonatal Nuclear Oxidoreductase Pathogenesis Pathway interactions Patients Phenotype Physiological Problem Solving Prosthesis Proteins RNA Binding RNA-Binding Proteins Rare Diseases Regulation Respiratory Chain Respiratory physiology Role Scaffolding Protein Sideroblastic Anemia Skeletal Muscle Succinate Dehydrogenase Sulfur Sulofenur Thioctic Acid Tissues Work candidate identification frataxin gene product human disease iron deficiency lymphoblast metabolic abnormality assessment skeletal muscle metabolism

项目摘要

IRP1 is an iron-sulfur protein related to mitochondrial aconitase, a citric acid cycle enzyme, and it functions as a cytosolic aconitase in cells that are iron replete. Regulation of RNA binding activity of IRP1 involves a transition from a form of IRP1 in which a 4Fe-4S cluster is bound, to a form that loses both iron and aconitase activity. The 4Fe-4S containing protein does not bind IREs. Controlled degradation of the iron-sulfur cluster and mutagenesis reveals that the physiologically relevant form of the RNA binding protein in iron-depleted cells is apoprotein. The status of the cluster appears to determine whether IRP1 will bind RNA. Over the past decade, we have identified mammalian enzymes of iron-sulfur cluster assembly that are homologous to the NifS, ISCU and Nif U, ferredoxin and ferredoxin reductase genes implicated in bacterial iron-sulfur cluster assembly, and we have shown that these gene products facilitate assembly of the iron- sulfur cluster of IRP1. We have discovered that frataxin transcription is iron-dependently regulated and frataxin expression decreases when there is cytosolic iron deficiency in wild-type and in fibroblasts and lymphoblasts from Friedreich ataxia patients. We discovered that a mutation in the scaffold protein, ISCU, causes a rare myopathy. In both Friedreich ataxia and ISCU myopathy, our data indicate that mitochondrial iron overload occurs in conjunction with cytosolic iron depletion. In collaboration, we discovered that NFU1 and BOLA3 mutations cause a human disease characterized by lactic acidosis and lipoic acid deficiency. We predicted that other rare genetic diseases characterized by mitochondrial compromise were caused by mutations in the genes responsible for iron-sulfur cluster biogenesis, and we collaborated to discover that mutations of NFS1 cause neonatal mitochondrial disease. We are characterizing the steps that chaperone transfer of nascent iron-sulfur clusters from their association with the initial assembly apparatus to proteins that require iron-sulfur clusters for function. We have extensively studied the metabolic remodeling of skeletal muscle metabolism in ISCU myopathy and discovered several compensatory pathways that help to maintain energy homeostasis. We have also discovered multiple reasons that limit the phenotype of ISU myopathy to skeletal muscles, while largely sparing other tissues. We are developing antisense treatment therapy for ISCU myopathy, and we recently demonstrated that FGF21 is a good biomarker for muscle disease in ISCU myopathy. We are also actively working to discover how SDHB acquires its three Fe-S clusters, and we have demonstrated that HSC20 cochaperone mediated iron sulfur cluster delivery is critical for iron sulfur acquisition of respiratory chains I-III. We are evaluating many more candidate recipients of iron sulfur clusters, and we expect our studies will greatly increase the number of known mammalian iron sulfur proteins.

IRP1 是一种与线粒体乌头酸酶（一种柠檬酸循环酶）相关的铁硫蛋白，它在铁充足的细胞中充当胞质乌头酸酶。 IRP1 RNA 结合活性的调节涉及从结合 4Fe-4S 簇的 IRP1 形式到失去铁和乌头酸酶活性的形式的转变。含有 4Fe-4S 的蛋白质不结合 IRE。铁硫簇的受控降解和诱变揭示了铁耗尽细胞中 RNA 结合蛋白的生理相关形式是脱辅基蛋白。簇的状态似乎决定了 IRP1 是否会结合 RNA。在过去的十年中，我们已经鉴定了与NifS、ISCU和Nif U同源的哺乳动物铁硫簇组装酶、与细菌铁硫簇组装有关的铁氧还蛋白和铁氧还蛋白还原酶基因，并且我们已经证明这些基因产物促进 IRP1 铁硫簇的组装。我们发现，frataxin 转录是铁依赖性调节的，当野生型以及来自 Friedreich 共济失调患者的成纤维细胞和淋巴母细胞中存在胞质铁缺乏时，frataxin 表达会降低。我们发现支架蛋白 ISCU 的突变会导致一种罕见的肌病。在弗里德赖希共济失调和 ISCU 肌病中，我们的数据表明线粒体铁超载与细胞质铁耗竭同时发生。通过合作，我们发现 NFU1 和 BOLA3 突变会导致一种以乳酸酸中毒和硫辛酸缺乏为特征的人类疾病。我们预测其他以线粒体受损为特征的罕见遗传病是由负责铁硫簇生物发生的基因突变引起的，我们合作发现 NFS1 的突变会导致新生儿线粒体疾病。我们正在描述新生铁硫簇分子伴侣从与初始组装装置的关联转移到需要铁硫簇发挥功能的蛋白质的步骤。我们广泛研究了 ISCU 肌病中骨骼肌代谢的代谢重塑，并发现了几种有助于维持能量稳态的代偿途径。我们还发现了多种原因，将 ISU 肌病的表型限制在骨骼肌，同时很大程度上不影响其他组织。我们正在开发针对 ISCU 肌病的反义治疗疗法，并且我们最近证明 FGF21 是 ISCU 肌病肌肉疾病的良好生物标志物。我们还积极致力于探索 SDHB 如何获取其三个 Fe-S 簇，并且我们已经证明 HSC20 共伴侣介导的铁硫簇递送对于呼吸链 I-III 的铁硫获取至关重要。我们正在评估更多铁硫簇的候选受体，我们预计我们的研究将大大增加已知哺乳动物铁硫蛋白的数量。