Temperature and Mg2+ Sensing by a Novel PhoP-PhoQ Two-component System for Regulation of Virulence in Edwardsiella tarda
Temperature and Mg2+ Sensing by a Novel PhoP-PhoQ Two-component System for Regulation of Virulence in Edwardsiella tarda
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DOI：
10.1074/jbc.m110.179150
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发表时间：
2010-12-01
影响因子：
4.8
通讯作者：
Mok, Yu-Keung
中科院分区：
文献类型：
--
作者：
Chakraborty, Smarajit;Li, Mo;Mok, Yu-Keung
PhoP-PhoQ双组分系统通常被细菌用来感知环境因素。在这里，我们表明，缓慢爱德华氏菌的PhoP-PhoQ系统检测环境温度和Mg 2+浓度的变化，以及通过直接激活esrB调节III型和VI型分泌系统。蛋白质分泌在23 - 35 ℃或低Mg 2+浓度下被激活，但在20 ℃或低于20 ℃、37 ℃或高于37 ℃或高Mg 2+浓度下被抑制。温度和Mg ~（2+）浓度的影响是加和的。PhoQ传感器结构域具有37.9摄氏度的低Tm，并且它通过其二级结构的构象变化来检测温度。特定Pro或Thr残基的突变大大增加了PhoQ传感器的稳定性，改变了其温度传感能力。PhoQ传感器通过Mg 2+与酸性残基簇（DDDSAD）的直接结合以及可能影响其三级结构的变化来检测Mg 2+浓度。在这里，我们描述了第一次使用的PhoP-PhoQ作为温度传感器的细菌毒力控制。
The PhoP-PhoQ two-component system is commonly used by bacteria to sense environmental factors. Here we show that the PhoP-PhoQ system of Edwardsiella tarda detects changes in environmental temperature and Mg2+ concentration as well as regulates the type III and VI secretion systems through direct activation of esrB. Protein secretion is activated from 23 to 35 degrees C or at low Mg2+ concentrations, but it is suppressed at or below 20 degrees C, at or above 37 C, or at high Mg2+ concentrations. The effects of temperature and Mg2+ concentration are additive. The PhoQ sensor domain has a low T-m of 37.9 degrees C, and it detects temperatures through a conformational change of its secondary structure. Mutation of specific Pro or Thr residues increased the stability of the PhoQ sensor drastically, altering its temperature-sensing ability. The PhoQ sensor detects Mg2+ concentration through the direct binding of Mg2+ to a cluster of acidic residues (DDDSAD) and through changes that likely affect its tertiary structure. Here, we describe for the first time the use of PhoP-PhoQ as a temperature sensor for bacterial virulence control.