Intracellular translocation and localization of Edwardsiella tarda type III secretion system effector EseG in host cells
Intracellular translocation and localization of Edwardsiella tarda type III secretion system effector EseG in host cells
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迟缓爱德华氏菌 III 型分泌系统效应子 EseG 在宿主细胞内的细胞内易位和定位
DOI：
10.1016/j.micpath.2016.05.008
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发表时间：
2016-08-01
影响因子：
3.8
通讯作者：
Liu, Qin
中科院分区：
文献类型：
--
作者：
Fang, Shan;Zhang, Lingzhi;Liu, Qin
迟缓爱德华氏菌（Edwardsiella tarda）是一种重要的鱼类致病菌，在感染过程中可利用III型分泌系统（T3SS）将多种效应蛋白转运到宿主细胞内。EseG被鉴定为迟缓爱德华氏菌的一种T3SS效应蛋白，它可由T3SS注入非吞噬细胞。由于迟缓爱德华氏菌是一种兼性胞内病原体，可在巨噬细胞内驻留和复制，因此拓展我们对EseG在吞噬细胞内的转运和定位的认识是很有意义的。在此，我们利用小鼠巨噬细胞系J1774A.1作为细胞模型，证明了只有在迟缓爱德华氏菌被巨噬细胞内化之后，EseG才能通过T3SS转运到J1774A.1细胞内，这表明细胞外的迟缓爱德华氏菌无法将EseG注入宿主细胞。亚细胞组分分析证明EseG特异性定位于受感染宿主细胞的膜组分。此外，免疫荧光检测表明EseG特异性靶向巨噬细胞内含有迟缓爱德华氏菌的空泡（ECV5）。最后，EseG的这些独特特征在非吞噬细胞中也得到了证实。总之，这项工作阐明了迟缓爱德华氏菌T3SS效应蛋白在非吞噬细胞和吞噬细胞中依赖内化的转运以及靶向ECV的定位，这可能对解释感染时EseG与宿主细胞的相互作用具有重要意义。（C）2016爱思唯尔有限公司。保留所有权利。
Edwardsiella tarda, an important fish pathogenic bacterium, could utilize type III secretion system (T3SS) to transfer multiple effector proteins into host cells during infection. EseG was identified to be an E tarda T3SS effector, which could be injected by T3SS into non-phagocytic cells. Since E. tarda is a facultative intracellular pathogen that resides and replicates in macrophage, it is interesting to expand our knowledge about EseG translocation and localization within phagocytic cells. Here utilizing murine macrophage cell line J1774A.1 as the cell model, we demonstrated that EseG could be transported into 1774A.1 via T3SS only after E. tarda was internalized into macrophage cells, indicating that extracellular E. tarda could not inject EseG into host cells. Subcellular fractionation analysis gave the evidence that EseG was specifically localized in the membrane fraction of infected host cells. Furthermore, immunofluorescence detection indicated that EseG specifically targeted the E. tarda-containing vacuoles (ECV5) within macrophage cells. Finally the unique features for EseG were also confirmed in non-phagocytic cells. In summarize, this work illuminates internalization-depending translocation and ECV-targeting localization of E. tarda T3SS effector in both non-phagocytic and phagocytic cells, which might be important to interpret the interaction of EseG with host cells upon infection. (C) 2016 Elsevier Ltd. All rights reserved.