Activated by Different Signals, the PhoP/PhoQ Two-Component System Differentially Regulates Metal Uptake

被引:47
作者
Choi, Eunna [1 ]
Groisman, Eduardo A. [2 ]
Shin, Dongwoo [1 ]
机构
[1] Sungkyunkwan Univ, Samsung Biomed Res Inst, Dept Mol Cell Biol, Sch Med, Suwon 440746, South Korea
[2] Washington Univ, Dept Mol Microbiol, Howard Hughes Med Inst, Sch Med, St Louis, MO 63110 USA
关键词
ENTERICA SEROVAR TYPHIMURIUM; BACTERIAL SENSOR KINASE; ESCHERICHIA-COLI K-12; FERROUS IRON UPTAKE; SALMONELLA-TYPHIMURIUM; MAGNESIUM TRANSPORT; MOLECULAR CHARACTERIZATION; EXTRACELLULAR IRON; TARGET PROMOTERS; PHOP-PHOQ;
D O I
10.1128/JB.00958-09
中图分类号
Q93 [微生物学];
学科分类号
071005 ; 100705 ;
摘要
The PhoP/PhoQ two-component system controls several physiological and virulence functions in Salmonella enterica. This system is activated by low Mg2+, acidic pH, and antimicrobial peptides, but the biological consequences resulting from sensing multiple signals are presently unclear. Here, we report that the PhoP/PhoQ system regulates different Salmonella genes depending on whether the inducing signal is acidic pH or low Mg2+. When Salmonella experiences acidic pH, the PhoP/PhoQ system promotes Fe2+ uptake in a process that requires the response regulator RstA, activating transcription of the Fe2+ transporter gene feoB. In contrast, the PhoP-induced RstA protein did not promote feoB expression at neutral pH with low Mg2+. The PhoP/PhoQ system promotes the expression of the Mg2+ transporter mgtA gene only when activated in bacteria starved for Mg2+. This is because mgtA transcription promoted at high Mg2+ concentrations by the acidic-pH-activated PhoP protein failed to reach the mgtA coding region due to the mgtA leader region functioning as a Mg2+ sensor. Our results show that a single two-component regulatory system can regulate distinct sets of genes in response to different input signals.
引用
收藏
页码:7174 / 7181
页数:8
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