Host cell type-dependent translocation and PhoP-mediated positive regulation of the effector SseK1 of Salmonella enterica.
Host cell type-dependent translocation and PhoP-mediated positive regulation of the effector SseK1 of Salmonella enterica.
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DOI：
10.3389/fmicb.2015.00396
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发表时间：
2015
影响因子：
5.2
通讯作者：
Ramos-Morales F
中科院分区：
文献类型：
--
作者：
Baisón-Olmo F;Galindo-Moreno M;Ramos-Morales F
肠道沙门氏菌表达两个毒力相关III型分泌系统（T3 SS），分别编码沙门氏菌致病岛1（SPI 1）和SPI 2。SseK 1是SPI 2编码的T3 SS的一种表征较差的底物。在这里，我们表明，这种效应是必不可少的，以获得完整的毒力在口服和腹腔内小鼠感染，尽管没有在培养的哺乳动物细胞的入侵或细胞内增殖的作用。在体外，当诱导SPI 2时，在模拟细胞内条件的培养基中sseK 1的表达更高，但在SPI 1诱导条件下也是显著的。对SseK 1易位到宿主细胞中的详细分析揭示，它是T3 SS 1和T3 SS 2的底物，尽管根据特定的宿主细胞类型（上皮细胞、巨噬细胞或成纤维细胞）具有不同的模式和动力学。使用lacZ和生物发光lux融合检测sseK 1表达的调节。双组分系统PhoQ/PhoP是该基因的正调控因子。序列分析，定向诱变和电泳迁移率变动分析的组合表明，磷酸化的PhoP直接结合到sseK 1的启动子区域，并揭示了一个PhoP的结合位点位于该启动子的预测-35六聚体的上游。
Salmonella enterica expresses two virulence-related type III secretion systems (T3SSs) encoded in Salmonella pathogenicity island 1 (SPI1) and SPI2, respectively. SseK1 is a poorly characterized substrate of the SPI2-encoded T3SS. Here, we show that this effector is essential to get full virulence both in oral and intraperitoneal mice infections, in spite of not having a role in invasion or intracellular proliferation in cultured mammalian cells. In vitro, expression of sseK1 was higher in media mimicking intracellular conditions, when SPI2 was induced, but it was also significant under SPI1 inducing conditions. A detailed analysis of translocation of SseK1 into host cells unveiled that it was a substrate of both, T3SS1 and T3SS2, although with different patterns and kinetics depending on the specific host cell type (epithelial, macrophages, or fibroblasts). The regulation of the expression of sseK1 was examined using lacZ and bioluminescent lux fusions. The two-component system PhoQ/PhoP is a positive regulator of this gene. A combination of sequence analysis, directed mutagenesis and electrophoretic mobility shift assays showed that phosphorylated PhoP binds directly to the promoter region of sseK1 and revealed a PhoP binding site located upstream of the predicted -35 hexamer of this promoter.
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影响因子：
3.5
作者：
CHEREPANOV, PP;WACKERNAGEL, W
通讯作者：
WACKERNAGEL, W
DOI：
10.1073/pnas.86.18.7077
发表时间：
1989-09-01
影响因子：
11.1
作者：
GROISMAN, EA;CHIAO, E;HEFFRON, F
通讯作者：
HEFFRON, F
影响因子：
3.6
作者：
Bajaj, V;Hwang, C;Lee, CA
通讯作者：
Lee, CA
影响因子：
3.5
作者：
Ellermeier, CD;Janakiraman, A;Slauch, JM
通讯作者：
Slauch, JM
影响因子：
3.7
作者：
Cardenal-Muñoz E;Ramos-Morales F
通讯作者：
Ramos-Morales F