Regulation of Iron Metabolism Genes in Eukaryotes

真核生物中铁代谢基因的调控

• 批准号: 6697269
• 负责人: WILLIAM EDWARD WALDEN
• 金额: $ 24.66万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-01-01 至 2006-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6697269
• 关键词: RNA binding protein; Saccharomyces cerevisiae; aconitate hydratase; enzyme activity; free radical oxygen; fungal genetics; gene expression; genetic manipulation; genetic regulation; immunoprecipitation; iron metabolism; iron sulfur protein; microarray technology; molecular assembly /self assembly; molecular genetics; mutant; nutrition related tag; oxidizing agents; protein biosynthesis; protein structure function

Iron is an essential element for nearly all forms of life. One of the challenges for organisms is the acquisition of iron due to its propensity to oxidize in aerobic environments and the extreme insolubility of ferric iron. As a result, organisms have evolved elaborate mechanisms for acquiring and storing iron. These mechanisms must be tightly regulated, however, due to the toxicity of free iron through its ability to catalyze the generation of free radicals through the Fenton reaction. In fact, aberrant iron regulation is associated with a variety of diseases and disorders in humans, including hemochromatosis, sideroblastic anemias, and Friedrich's ataxia, to name a few. Animals regulate iron uptake and storage primarily through the action of iron regulatory proteins (IRP), a family of sequence- specific, RNA binding proteins. IRPs regulate the synthesis of ferritin and transferrin receptor, proteins that serve in iron storage and iron transport, respectively. Through this regulation, animal cells are able to maintain iron homeostasis. IRPs also regulate the synthesis of proteins that are involved in heme biosynthesis and energy production. Thus the role of IRPs in cellular physiology is broader than simply iron regulation. There are two IRP family members, called IRP1 and IRP2. IRP1 is a bifunctional protein having the aforementioned activity as a RNA binding, gene regulator, or as the cytosolic isoform of aconitase. These activities are mutually exclusive and require the assembly and disassembly of a [4Fe-4S] cluster in the protein. Therefore, the activity of IRP1 and the regulation of iron in animals is dependent on the reversible assembly of an Fe- S cluster in this protein. In the proposed studies, we will define the mechanism and factors involved in the assembly/disassembly of the Fe-S cluster in IRP1. We will use a combination of molecular genetic, genetic and biochemical techniques in the yeast, Saccharomyces cerevisiae, to accomplish our goals. Our specific aims are to: 1) Define the mechanism of Fe-S cluster assembly in IRP1; 2) Determine the mechanism by which iron disrupts IRE/IRP1 complexes; 3) Investigate the process of Fe-S cluster disassembly in IRP1. The completion of these studies will help us to understand how organisms utilize Fe-S clusters as sensors of cellular iron status and oxidant levels as well as giving us insight into the fundamental question of Fe-S cluster assembly.

铁是几乎所有形式的生命的重要元素。 生物体的挑战之一是铁在有氧环境中氧化和铁铁的极端不溶性，因此获得了铁。 结果，生物已经发展出精心的获取和储存铁的机制。但是，由于自由铁的毒性通过芬顿反应催化产生自由基的能力，必须严格调节这些机制。 实际上，异常的铁调节与人类的多种疾病和疾病有关，包括血色素症，副细胞性贫血和弗里德里希共济失调，仅举几例。动物主要通过铁调节蛋白（IRP）的作用来调节铁的摄取和储存，这是一个序列特异性的，RNA结合蛋白的家族。 IRPS调节铁蛋白和转铁蛋白受体的合成，分别用于铁储存和铁运输的蛋白质。 通过这种调节，动物细胞能够维持铁稳态。 IRP还调节与血红素生物合成和能量产生有关的蛋白质的合成。 因此，IRP在细胞生理学中的作用远不仅是铁调节。有两个IRP家庭成员，称为IRP1和IRP2。 IRP1是一种双功能蛋白，上述活性是RNA结合，基因调节剂或作为刺刺酶的胞质同工型。 这些活动是相互排斥的，需要在蛋白质中[4FE-4S]簇的组装和拆卸。 因此，IRP1的活性和动物中铁的调节取决于该蛋白质中Fe-s组的可逆组装。 在拟议的研究中，我们将定义IRP1中Fe-S群集组装/拆卸的机制和因素。 我们将使用酵母中酿酒酵母中的分子遗传，遗传和生化技术的结合来实现我们的目标。 我们的具体目的是：1）定义IRP1中Fe-S群集组装的机理； 2）确定铁破坏IRE/IRP1复合物的机制； 3）研究IRP1中Fe-S簇拆卸的过程。 这些研究的完成将有助于我们了解生物如何利用Fe-S簇作为细胞铁状态和氧化剂水平的传感器，并使我们深入了解Fe-S群集组装的基本问题。