Natural resistance to infection with intracellular pathogens: the Nramp1 protein is recruited to the membrane of the phagosome.
Natural resistance to infection with intracellular pathogens: the Nramp1 protein is recruited to the membrane of the phagosome.
复制标题
细胞内病原体对感染的自然耐药性：将NRAMP1蛋白募集到吞噬体的膜上。
DOI：
10.1084/jem.185.4.717
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发表时间：
1997-02-17
期刊：
影响因子：
--
通讯作者：
Gros P
中科院分区：
文献类型：
--
作者：
Gruenheid S;Pinner E;Desjardins M;Gros P
Nramp1（自然抵抗相关巨噬细胞蛋白 1）位点（Bcg、Ity、Lsh）控制小鼠对一组不相关的细胞内寄生虫（包括沙门氏菌、利什曼原虫和分枝杆菌）感染的先天抵抗力或易感性。 Nramp1 仅在专业吞噬细胞中表达，并编码与离子通道和转运蛋白具有相同结构特征的整合膜蛋白。其功能和作用机制仍不清楚。通过免疫荧光和共聚焦显微镜以及生化分级分离，在对照 129/sv 和突变型 Nramp1− /− 巨噬细胞中分析了 Nramp1 蛋白的细胞内定位。在使用特异性抗 Nramp1 抗血清和一组针对已知细胞结构的对照抗体进行的共定位研究中，发现 Nramp1 不在质膜上表达，而是定位于 Lamp1（溶酶体相关膜蛋白 1）阳性区室中静息巨噬细胞的晚期内吞区室（晚期内体/溶酶体）。双重免疫荧光研究和含乳胶珠的吞噬体的直接纯化表明，在吞噬作用下，Nramp1 被招募到吞噬体的膜上，并在其成熟为吞噬溶酶体的过程中保持与该结构的联系。吞噬作用后，Nramp1 被吞噬体膜捕获，其时间动力学与 Lamp1 相似，但与早期内体标记 Rab5 的时间动力学明显不同。 Nramp1 从内吞囊泡到吞噬体膜的靶向支持了这样的假设：Nramp1 通过改变含有微生物的吞噬体的液泡内环境来控制细胞内寄生虫的复制。
The Nramp1 (natural-resistance-associated macrophage protein 1) locus (Bcg, Ity, Lsh) controls the innate resistance or susceptibility of mice to infection with a group of unrelated intracellular parasites which includes Salmonella, Leishmania, and Mycobacterium. Nramp1 is expressed exclusively in professional phagocytes and encodes an integral membrane protein that shares structural characteristics with ion channels and transporters. Its function and mechanism of action remain unknown. The intracellular localization of the Nramp1 protein was analyzed in control 129/sv and mutant Nramp1− /− macrophages by immunofluorescence and confocal microscopy and by biochemical fractionation. In colocalization studies with a specific anti-Nramp1 antiserum and a panel of control antibodies directed against known cellular structures, Nramp1 was found not to be expressed at the plasma membrane but rather localized to the late endocytic compartments (late endosome/lysosome) of resting macrophages in a Lamp1 (lysosomal-associated membrane protein 1)-positive compartment. Double immunofluorescence studies and direct purification of latex bead–containing phagosomes demonstrated that upon phagocytosis, Nramp1 is recruited to the membrane of the phagosome and remains associated with this structure during its maturation to phagolysosome. After phagocytosis, Nramp1 is acquired by the phagosomal membrane with time kinetics similar to Lamp1, but clearly distinct from those of the early endosomal marker Rab5. The targeting of Nramp1 from endocytic vesicles to the phagosomal membrane supports the hypothesis that Nramp1 controls the replication of intracellular parasites by altering the intravacuolar environment of the microbe-containing phagosome.