The phosphotransferase protein EIIA(Ntr)  modulates the phosphate starvation response through interaction with histidine kinase PhoR in Escherichia coli.
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.
Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August-University, Grisebachstrasse 8, 37077 Göttingen, Germany.
Denise
D
Lüttmann
Yvonne
Y
Göpel
Boris
B
Görke
D019677:Artificial Gene Fusion; D001426:Bacterial Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D010710:Phosphates / Q000378:metabolism; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics / Q000378:metabolism*; D025941:Protein Interaction Mapping; D001616:beta-Galactosidase / Q000032:analysis / Q000235:genetics
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D010710:Phosphates; C061279:PhoR protein, Bacteria; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C529959:PtsN protein, E coli; D001616:beta-Galactosidase