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The phosphotransferase protein EIIA Ntr modulates the phosphate starvation response through interaction with histidine kinase PhoR in Escherichia coli
Author(s) -
Lüttmann Denise,
Göpel Yvonne,
Görke Boris
Publication year - 2012
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2012.08176.x
Subject(s) - pep group translocation , regulon , response regulator , histidine kinase , biology , two component regulatory system , operon , kinase , mutant , phosphotransferase , biochemistry , phosphorylation , histidine , phosphoenolpyruvate carboxykinase , escherichia coli , microbiology and biotechnology , gene , enzyme
Summary Many Proteobacteria possess the paralogous PTS Ntr , in addition to the sugar transport phosphotransferase system (PTS). In the PTS Ntr phosphoryl‐groups are transferred from phosphoenolpyruvate to protein EIIA Ntr via the phosphotransferases EI Ntr and NPr. The PTS Ntr has been implicated in regulation of diverse physiological processes. In Escherichia coli , the PTS Ntr plays a role in potassium homeostasis. In particular, EIIA Ntr binds to and stimulates activity of a two‐component histidine kinase (KdpD) resulting in increased expression of the genes encoding the high‐affinity K + transporter KdpFABC. Here, we show that the phosphate ( pho ) regulon is likewise modulated by PTS Ntr . The pho regulon, which comprises more than 30 genes, is activated by the two‐component system PhoR/PhoB under conditions of phosphate starvation. Mutants lacking EIIA Ntr are unable to fully activate the pho genes and exhibit a growth delay upon adaptation to phosphate limitation. In contrast, pho expression is increased above the wild‐type level in mutants deficient for EIIA Ntr phosphorylation suggesting that non‐phosphorylated EIIA Ntr modulates pho . Protein interaction analyses reveal binding of EIIA Ntr to histidine kinase PhoR. This interaction increases the amount of phosphorylated response regulator PhoB. Thus, EIIA Ntr is an accessory protein that modulates the activities of two distinct sensor kinases, KdpD and PhoR, in E. coli .