The sigma(E) and the Cpx signal transduction systems control the synthesis of periplasmic protein-folding enzymes in Escherichia coli
The sigma(E) and the Cpx signal transduction systems control the synthesis of periplasmic protein-folding enzymes in Escherichia coli
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DOI：
10.1101/gad.11.9.1183
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发表时间：
1997-05-01
影响因子：
10.5
通讯作者：
Silhavy, TJ
中科院分区：
文献类型：
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作者：
Danese, PN;Silhavy, TJ
在大肠杆菌中，热休克诱导的σ-因子σ（E）和Cpx双组分信号转导系统都与胞质外刺激相协调。例如，sigma（E）活性响应于各种外膜蛋白的过量产生而升高。类似地，由内膜传感器（CpxA）和同源反应调节器（CpxR）组成的Cpx信号转导途径的活性由外膜脂蛋白NlpE的过量产生刺激。响应于这些胞质外刺激，sigma（E）和CpxA/CpxR刺激编码周质蛋白酶的degP的转录。这表明CpxA/CpxR和sigma（E）都介导细菌包膜内的蛋白质周转。在这里，我们表明，CpxA/CpxR和sigma（E）也控制周质酶的合成，可以促进蛋白质折叠反应。具体地，sigma（E）控制FkpA的转录，其指定周质肽基-脯氨酰顺式/反式异构酶。类似地，Cpx系统控制dsbA基因座的转录，dsbA基因座编码在几种胞质外蛋白中有效形成二硫键所需的周质酶。综上所述，这些结果表明sigma（E）和CpxA/CpxR参与调节细菌包膜内的蛋白质周转和蛋白质折叠活性。
In Escherichia coli, the heat shock-inducible sigma-factor sigma(E) and the Cpx two-component signal transduction system are both attuned to extracytoplasmic stimuli. For example, sigma(E) activity rises in response to the overproduction of various outer-membrane proteins. Similarly, the activity of the Cpx signal transduction pathway, which consists of an inner-membrane sensor (CpxA) and a cognate response regulator (CpxR), is stimulated by overproduction of the outer-membrane lipoprotein, NlpE. In response to these extracytoplasmic stimuli, sigma(E) and CpxA/CpxR stimulate the transcription of degP, which encodes a periplasmic protease. This suggests that CpxA/CpxR and sigma(E) both mediate protein turnover within the bacterial envelope. Here, we show that CpxA/CpxR and sigma(E) also control the synthesis of periplasmic enzymes that can facilitate protein-folding reactions. Specifically, sigma(E) controls transcription of FkpA, which specifies a periplasmic peptidyl-prolyl cis/trans isomerase. Similarly, the Cpx system controls transcription of the dsbA locus, which encodes a periplasmic enzyme required for efficient disulfide bond formation in several extracytoplasmic proteins. Taken together, these results indicate that sigma(E) and CpxA/CpxR are involved in regulating both protein-turnover and protein-folding activities within the bacterial envelope.