Inclusion Membrane Proteins of Protochlamydia amoebophila UWE25 Reveal a Conserved Mechanism for Host Cell Interaction among the Chlamydiae
Inclusion Membrane Proteins of Protochlamydia amoebophila UWE25 Reveal a Conserved Mechanism for Host Cell Interaction among the Chlamydiae
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DOI：
10.1128/jb.00605-10
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发表时间：
2010-10-01
影响因子：
3.2
通讯作者：
Horn, Matthias
中科院分区：
文献类型：
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作者：
Heinz, Eva;Rockey, Daniel D.;Horn, Matthias
衣原体是一组专性细胞内细菌，包括几种重要的人类病原体。在真核细胞内，衣原体保持在宿主衍生的囊泡腔内，称为包涵体。它们通过插入独特的蛋白质来修饰包涵膜，这些蛋白质参与与宿主细胞的相互作用和操纵。在衣原体中，包涵膜蛋白仅在衣原体科成员中发现，衣原体主要感染哺乳动物和鸟类宿主。本文报道了自由生活的变形虫的衣原体内共生体——拟变形虫原衣原体UWE25中包涵膜蛋白的存在。二级结构基序的全基因组筛选结果鉴定了该生物的23个推定包涵膜蛋白。免疫荧光分析表明，其中5种蛋白被表达，其中4种可以定位在细胞内细菌周围的晕上。共定位研究表明，四种假定的包涵膜蛋白的信号几乎完全重叠，免疫透射电子显微镜明确地证明了它们在包涵膜中的位置。在拟变形虫中存在包涵膜蛋白（被命名为IncA、IncQ、IncR和IncS）表明，这种寄主细胞相互作用的策略在衣原体中是保守的，并被衣原体共生体和病原体所使用。
Chlamydiae are a group of obligate intracellular bacteria comprising several important human pathogens. Inside the eukaryotic cell, chlamydiae remain within a host-derived vesicular compartment, termed the inclusion. They modify the inclusion membrane through insertion of unique proteins, which are involved in interaction with and manipulation of the host cell. Among chlamydiae, inclusion membrane proteins have been exclusively found in members of the family Chlamydiaceae, which predominantly infect mammalian and avian hosts. Here, the presence of inclusion membrane proteins in Protochlamydia amoebophila UWE25, a chlamydial endosymbiont of free-living amoebae, is reported. A genome-wide screening for secondary structure motifs resulted in the identification of 23 putative inclusion membrane proteins for this organism. Immunofluorescence analysis demonstrated that five of these proteins were expressed, and four of them could be localized to a halo surrounding the intracellular bacteria. Colocalization studies showed an almost complete overlap of the signals obtained for the four putative inclusion membrane proteins, and immuno-transmission electron microscopy unambiguously demonstrated their location in the inclusion membrane. The presence of inclusion membrane proteins (designated IncA, IncQ, IncR, and IncS) in P. amoebophila shows that this strategy for host cell interaction is conserved among the chlamydiae and is used by chlamydial symbionts and pathogens alike.