REGULATION OF NRAMP1 MEDIATED IRON TRANSPORT

说明(改编自应用程序) 巨噬细胞是维持铁稳态的中心细胞，扮演着主要的 体内铁储存部位(1-3个)。铁也是巨噬细胞的一个主要因素。 抗微生物防御，在产生反应中起到催化剂的作用 羟基自由基(4-6)。小鼠(9-11)的Nramp1基因控制自然 对多种细胞内病原体感染的抵抗力。基因是存在的 作为两种等位基因形式，它们决定了对生长的抗性或敏感性 在感染的早期阶段，巨噬细胞内的这些病原体。这个 蛋白质在巨噬细胞的内吞囊泡中表达，巨噬细胞的内吞囊泡运输到 噬菌体。感病等位基因与抗病等位基因相差一个 甘氨酸在第四跨膜结构域上被天冬氨酸取代。我们的 实验室研究了Nramp1在巨噬细胞抗微生物中的作用 活跃度和铁代谢。我们已经证明了Nramp1将铁输送到 吞噬小体，其中铁起催化哈伯-韦斯反应的作用。这个 由此产生的反应性羟基自由基的产生抑制了 吞噬细菌。我们的观察表明，Nramp是一种 通过将铁转运到吞噬体内的抗菌活性是基础 以确定调节Nramp1介导的铁的因素 运输。我们的具体目标是：1.确定Nramp1介导的调控 铁转运；2.确定Nramp1转运铁是否需要蛋白质 磷酸化和3.通过定点突变来确定结构域 在影响铁运输的Nramp1蛋白中。

DESCRIPTION (adapted from the application) Macrophages are central to maintenance of iron homeostasis, acting as a major iron storage site in the body (1-3). Iron is also a major factor in macrophage anti-microbial defense, acting as a catalyst in the generation of reactive hydroxyl radicals (4-6). The Nramp1 gene in mice (9-11) controls natural resistance to infection by a number of intracellular pathogens. The gene exists as two allelic forms that determine resistance or susceptibility to growth of these pathogens within macrophages during the early stages of infection. The protein is expressed in endocytic vesicles of macrophages that traffic to the phagosome. The susceptible allele differs from the resistant allele by a single glycine to aspartic acid substitution in the fourth transmembrane domain. Our laboratory has investigated the role of Nramp1 in macrophage antimicrobial activity and in iron metabolism. We have shown that Nramp1 transports iron into phagosomes where the iron serves to catalyze the Haber-Weiss reaction. The resulting production of reactive hydroxyl radical then inhibits the growth of the phagocytized bacteria. Our observations that Nramp serves as a regulator of antimicrobial activity by transporting iron into phagosomes serves as the basis of this application to determine the factors that regulate Nramp1 mediated iron transport. Our specific aims are: 1. To determine regulation of Nramp1 mediated iron transport; 2. To determine if iron transport by Nramp1 requires protein phosphorylation and 3. To determine, by site directed mutagenesis, the domains within the Nramp1 protein that affect iron transport.