Managing Ionic Iron: Molecular Architecture and Mechanism of Cell Iron Metabolism

管理离子铁：细胞铁代谢的分子结构和机制

• 批准号: 7615733
• 负责人: DANIEL J. KOSMAN
• 金额: $ 27.99万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT BUFFALO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7615733
• 关键词: AA Spectrophotometry; Abbreviations; Aerobic; Affinity; Age; Architecture; Back; Binding Proteins; Biochemical; Biochemistry; Bipyridyl; Cell membrane; Cells; Cellular biology; Ceruloplasmin; Chemistry; Classification; Complex; Corrosives; Coupled; Cytoplasm; Deferoxamine; Dioxygen; Endoplasmic Reticulum; Enzymes; Eukaryota; Eukaryotic Cell; Face; Ferritin; Fluorescence Resonance Energy Transfer; Focus Groups; Functional disorder; Genes; Glutathione; Hand; Heat shock proteins; Heat-Shock Proteins 90; Heme; Homeostasis; Homologous Gene; Human; Human Pathology; Ion Channel; Ions; Iron; Iron Compounds; Iron Regulatory Protein 1; Kinetics; Lead; Lip structure; Mammalian Cell; Maps; Membrane; Metabolic; Metabolic Pathway; Metabolism; Metals; Mitochondria; Modeling; Molecular; Molecular Chaperones; Mutation; Neurodegenerative Disorders; Nitric Oxide; Organic Iron Compounds; Organism; Oxidases; Oxidation-Reduction; Oxidoreductase; Oxygen; Pathology; Pathway interactions; Plasma; Play; Principal Investigator; Process; Production; Property; Prosthesis; Proteins; RNA Binding; RNA-Binding Proteins; Reaction; Recycling; Reduced Glutathione; Regulon; Relative (related person); Research; Research Personnel; Response Elements; Ribonucleotide Reductase; Role; SLC11A2 gene; Saccharomyces; Saccharomyces cerevisiae; Side; Signal Transduction; Site; Solubility; Solutions; Study Subject; Surface; Testing; Tissues; Transferrin; Transferrin Receptor; Vacuole; Water; Yeasts; base; cellular engineering; cytotoxic; dinitrosyl iron complex; divalent metal; ferrochelatase; frataxin; genome database; iron (III) reductase; iron metabolism; methylsterol monooxygenase; oxidation; permease; programs; protoporphyrin IX; sensor; spatial relationship; trafficking; transcription factor; uptake; yeast protein

DESCRIPTION (provided by applicant): The solution and redox properties of iron that make it the metal prosthetic group of choice for the activation of otherwise kinetically inert substrates, including dioxygen, also make ionic Fe cytotoxic to aerobic organisms. Eukaryotes from yeast to humans have to manage ferrous iron's inherent reactivity with dioxygen and ferric iron's instability in water; the oft-cited role of iron in human pathology from post-ischemic tissue damage to neurodegenerative disease is testament to the importance of managing ionic iron. We propose that the Fe-traffieking pathway that succeeds in suppressing Fe's abiologic side-reactions has two essential and inter-related features: sequential Fe-trafficking components are spatially contiguous and thereby are architecturally organized to support the channeling of ionic Fe species along the Fe-metabolic pathway. This model will be tested at three steps in the ionic Fe pathway in Saccaromyces cerevisiae, the most tractable eukaryotic cell for a systematic test of this Fe-metabolic model. These three steps are: at the plasma membrane where ferrireduction is coupled to iron permeation; in the cytoplasm where Fe is trafficked from the PM to protein acceptor sites; and in the vacuole where Fe-redox cycling is coupled to Fe-storage in reactions that precisely mirror those that occur in ferritin. A primary strategy to ascertain conformational contiguity of Fe-handling proteins will be fluorescence resonance energy transfer; we propose to use FRET to examine the spatial relationships between reductase and permease partners in the plasma and vacuolar membranes. A primary strategy in quantifying the relative partitioning of newly-arrived Fe will be the use of cells engineered to turn on or turn off production of these putative Fe-handling proteins. A new role in Fe- handling is proposed for the yeast HSP90 proteins, Hsp82 and Hsc82; in addition, we suggest that nitric oxide and glutathione combine in a dinitrosyldithiolato-Fe complex that plays a significant role in cytoplasmic Fe-handling. Outstanding progress has been made on the metabolism of Fe-prosthetic groups like heme and Fe/S clusters; ionic Fe is the precursor to these "caged" Fe-species and is responsible for the "corrosive chemistry" that characterizes the relationship between Fe and dioxygen. An understanding of how cells suppress this chemistry would make a significant contribution to our eventual elucidation of the molecular basis for the multitude of human pathologies often attributed in part to mismanaged ionic iron.

描述（由申请人提供）：铁的溶液和氧化还原特性使其成为激活其他动力学惰性底物（包括双氧）的金属辅基，同时也使离子铁对需氧生物体具有细胞毒性。从酵母到人类的真核生物必须控制二价铁与双氧的固有反应性以及三价铁在水中的不稳定性；铁在人类病理学（从缺血后组织损伤到神经退行性疾病）中经常被提及的作用证明了管理离子铁的重要性。我们认为，成功抑制 Fe 的非生物副反应的 Fe 运输途径具有两个基本且相互关联的特征：连续的 Fe 运输成分在空间上是连续的，因此在结构上组织起来以支持离子 Fe 物种沿 Fe 通道的通道。 -代谢途径。该模型将在酿酒酵母中的离子铁途径中的三个步骤进行测试，酿酒酵母是最容易处理的真核细胞，用于系统测试该铁代谢模型。这三个步骤是： 在质膜处，铁还原与铁渗透相结合；在细胞质中，Fe 从 PM 运输到蛋白质受体位点；在液泡中，铁氧化还原循环与铁储存耦合，反应精确反映了铁蛋白中发生的反应。确定铁处理蛋白构象连续性的主要策略是荧光共振能量转移；我们建议使用 FRET 来检查质膜和液泡膜中还原酶和渗透酶伙伴之间的空间关系。量化新到达的铁的相对分配的主要策略是使用经过改造的细胞来打开或关闭这些假定的铁处理蛋白的产生。酵母 HSP90 蛋白、Hsp82 和 Hsc82 在铁处理中发挥新作用；此外，我们认为一氧化氮和谷胱甘肽结合形成二亚硝基二硫醇-Fe 复合物，在细胞质 Fe 处理中发挥重要作用。在血红素、Fe/S簇等Fe辅基的代谢方面取得了突出进展；离子铁是这些“笼中”铁物质的前体，负责表征铁和分子氧之间关系的“腐蚀性化学”。了解细胞如何抑制这种化学反应，将为我们最终阐明多种人类病理的分子基础做出重大贡献，这些病理通常部分归因于离子铁管理不当。