A third envelope stress signal transduction pathway in Escherichia coli
A third envelope stress signal transduction pathway in Escherichia coli
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DOI：
10.1046/j.1365-2958.2002.03112.x
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发表时间：
2002-09-01
影响因子：
3.6
通讯作者：
Raivio, TL
中科院分区：
文献类型：
--
作者：
Raffa, RG;Raivio, TL
大肠杆菌使用重叠的包膜应激反应来适应细菌包膜的损伤，导致蛋白质错误折叠。sigma（E）和Cpx包膜应激反应由共同的和不同的包膜应激激活，并通过增加周质蛋白酶DegP以及每种应答特有的靶基因的表达来应答。sigma（E）途径参与外膜蛋白（OMP）折叠质量控制，而Cpx途径在至少一个菌毛的组装中起重要作用。以前，我们确定间谍基因作为一个新的Cpx调节子成员的未知功能。有趣的是，诱导间谍的表达严重的信封应力，如原生质球是只有部分依赖于一个完整的Cpx信号通路，不像其他Cpx调节基因。在这里，我们表明，BaeS传感器激酶和BaeR反应调节器也控制间谍在响应信封应力的表达。BaeS和BaeR不影响其他已知的Cpx调控基因的表达，然而，baeR cpxR双突变体显示出增加的敏感性，相对于任何单一的突变体单独的包膜应力。我们认为Bae信号转导途径控制着E.大肠杆菌中诱导一组独特的适应性基因的表达。
Escherichia coli uses overlapping envelope stress responses to adapt to insults to the bacterial envelope that cause protein misfolding. The sigma(E) and Cpx envelope stress responses are activated by both common and distinct envelope stresses and respond by increasing the expression of the periplasmic protease DegP as well as target genes unique to each response. The sigma(E) pathway is involved in outer membrane protein (OMP) folding quality control whereas the Cpx pathway plays an important role in the assembly of at least one pilus. Previously, we identified the spy gene as a new Cpx regulon member of unknown function. Interestingly, induction of spy expression by severe envelope stresses such as spheroplasting is only partially dependent on an intact Cpx signalling pathway, unlike other Cpx-regulated genes. Here we show that the BaeS sensor kinase and BaeR response regulator also control expression of spy in response to envelope stress. BaeS and BaeR do not affect expression of other known Cpx-regulated genes, however, baeR cpxR double mutants show increased sensitivity to envelope stresses relative to either single mutant alone. We propose that the Bae signal transduction pathway controls a third envelope stress response in E. coli that induces expression of a distinct set of adaptive genes.