Analysis of the expression, secretion and translocation of the Salmonella enterica type III secretion system effector SteA.
Analysis of the expression, secretion and translocation of the Salmonella enterica type III secretion system effector SteA.
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DOI：
10.1371/journal.pone.0026930
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发表时间：
2011
期刊：
影响因子：
3.7
通讯作者：
Ramos-Morales F
中科院分区：
文献类型：
--
作者：
Cardenal-Muñoz E;Ramos-Morales F
许多革兰氏阴性病原体具有毒力相关的III型分泌系统。肠道沙门氏菌使用这些系统中的两个，分别在致病岛SPI-1和SPI-2上编码，将超过30种效应蛋白转运到真核宿主细胞中。SteA是为数不多的可以被两个系统移位的效应物之一。我们研究了影响这种效应物的合成、其分泌到培养基及其易位到宿主细胞中的条件。而steA在广泛的条件下表达，一些因素，包括低和高渗透压，和丁酸盐的存在下，降低表达。在SPI-1和SPI-2诱导条件下，SteA均有效地分泌到培养基中。使用与3xFLAG标签的融合物和与来自百日咳博德特氏菌的CyaA的融合物研究易位到鼠巨噬细胞和人上皮细胞中的动力学。在非侵入性条件下转运到巨噬细胞中主要依赖于SPI-2编码的III型分泌系统，但在感染后6小时也检测到SPI-1系统的一些参与。有趣的是，这两种III型分泌系统在SteA易位到上皮细胞中具有相关作用。最后，一个删除的方法允许识别的N-末端的信号易位的这个效应。氨基酸残基1-10足以通过两种III型分泌系统直接易位到宿主细胞中。我们的研究结果提供了沙门氏菌的两个III型分泌系统之间的功能重叠的新的例子。
Many Gram-negative pathogens possess virulence-related type III secretion systems. Salmonella enterica uses two of these systems, encoded on the pathogenicity islands SPI-1 and SPI-2, respectively, to translocate more than 30 effector proteins into eukaryotic host cells. SteA is one of the few effectors that can be translocated by both systems. We investigated the conditions affecting the synthesis of this effector, its secretion to culture media and its translocation into host cells. Whereas steA was expressed under a wide range of conditions, some factors, including low and high osmolarity, and presence of butyrate, decreased expression. SteA was efficiently secreted to the culture media under both SPI-1 and SPI-2 inducing conditions. The kinetics of translocation into murine macrophages and human epithelial cells was studied using fusions with the 3xFLAG tag, and fusions with CyaA from Bordetella pertussis. Translocation into macrophages under non-invasive conditions was mainly dependent on the SPI-2-encoded type III secretion system but some participation of the SPI-1 system was also detected 6 hours post-infection. Interestingly, both type III secretion systems had a relevant role in the translocation of SteA into epithelial cells. Finally, a deletion approach allowed the identification of the N-terminal signal necessary for translocation of this effector. The amino acid residues 1–10 were sufficient to direct translocation into host cells through both type III secretion systems. Our results provide new examples of functional overlapping between the two type III secretion systems of Salmonella.
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影响因子：
15.9
作者：
Baumler, AJ
通讯作者：
Baumler, AJ
影响因子：
3.5
作者：
CHEREPANOV, PP;WACKERNAGEL, W
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WACKERNAGEL, W
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作者：
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通讯作者：
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影响因子：
3.1
作者：
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通讯作者：
Wallis, TS