REGULATION OF NRAMP1 MEDIATED IRON TRANSPORT

描述（改编自应用程序） 巨噬细胞对于维持铁稳态至关重要，是维持铁稳态的主要细胞。 体内铁的储存部位 (1-3)。铁也是巨噬细胞的主要因素 抗微生物防御，充当反应生成的催化剂 羟基自由基(4-6)。小鼠 (9-11) 中的 Nramp1 基因控制自然 对多种细胞内病原体的感染具有抵抗力。该基因存在 作为决定对生长的抗性或易感性的两种等位基因形式 在感染的早期阶段，这些病原体存在于巨噬细胞内。的 蛋白质在巨噬细胞的内吞小泡中表达，巨噬细胞运输到 吞噬体。易感等位基因与抗性等位基因有一个不同 第四跨膜结构域中甘氨酸被天冬氨酸取代。我们的 实验室研究了 Nramp1 在巨噬细胞抗菌中的作用 活性和铁代谢。我们已经证明 Nramp1 将铁转运到 吞噬体中的铁用于催化哈伯-韦斯反应。的 由此产生的反应性羟基自由基然后抑制生长 被吞噬的细菌。我们观察到 Nramp 充当调节者 通过将铁转运到吞噬体中的抗菌活性作为基础 该应用的目的是确定调节 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 钢铁运输； 2. 确定 Nramp1 的铁转运是否需要蛋白质 磷酸化和 3. 通过定点诱变确定结构域 Nramp1 蛋白内影响铁转运。

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.