IcmS-dependent translocation of SdeA into macrophages by the Legionella pneumophila type IV secretion system
IcmS-dependent translocation of SdeA into macrophages by the Legionella pneumophila type IV secretion system
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DOI：
10.1111/j.1365-2958.2005.04539.x
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发表时间：
2005-04-01
影响因子：
3.6
通讯作者：
Vogel, JP
中科院分区：
文献类型：
--
作者：
Bardill, JP;Miller, JL;Vogel, JP
嗜肺军团菌在肺泡巨噬细胞内复制，引起急性、潜在致命的肺炎，称为军团病。这种细菌在巨噬细胞内生长的能力取决于功能性dot/icm IV型分泌系统（T4 SS）的存在。由Dot/Icm T4 SS分泌的蛋白质被推测改变宿主的内吞途径，允许L. pneumophila在宿主细胞内建立复制生态位。在这里，我们表明，SidE家族的蛋白质与IcmS相互作用的成员，并在原生动物宿主卡氏阿米巴中的完整毒力所需的。使用免疫荧光显微镜和腺苷酸环化酶融合，我们表明，SdeA分泌到宿主细胞由L。pneumophila以IcmS依赖的方式。SidE样蛋白在巨噬细胞感染过程中很早就分泌，表明它们在复制性吞噬体的初始形成中很重要。分泌的SidE家族成员显示出与其他Dot/Icm底物类似的定位，特别是复制性吞噬体的两极。这种常见的本地化的点/Icm系统的分泌底物可能表明复制吞噬体的细胞质表面上的多蛋白复合物的形成。
Legionella pneumophila replicates inside alveolar macrophages and causes an acute, potentially fatal pneumonia called Legionnaires' disease. The ability of this bacterium to grow inside of macrophages is dependent on the presence of a functional dot/icm type IV secretion system (T4SS). Proteins secreted by the Dot/Icm T4SS are presumed to alter the host endocytic pathway, allowing L. pneumophila to establish a replicative niche within the host cell. Here we show that a member of the SidE family of proteins interacts with IcmS and is required for full virulence in the protozoan host Acanthamoeba castellanii. Using immunofluorescence microscopy and adenylate cyclase fusions, we show that SdeA is secreted into host cells by L. pneumophila in an IcmS-dependent manner. The SidE-like proteins are secreted very early during macrophage infection, suggesting that they are important in the initial formation of the replicative phagosome. Secreted SidE family members show a similar localization to other Dot/Icm substrates, specifically, to the poles of the replicative phagosome. This common localization of secreted substrates of the Dot/Icm system may indicate the formation of a multiprotein complex on the cytoplasmic face of the replicative phagosome.