Repression of Escherichia coli PhoP-PhoQ signaling by acetate reveals a regulatory role for acetyl coenzyme A.
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Lesley JA, Waldburger CD
Repression of Escherichia coli PhoP-PhoQ signaling by acetate reveals a regulatory role for acetyl coenzyme A.
J Bacteriol. 2003 Apr;185(8):2563-70.
- PubMed ID
- 12670981 [ View in PubMed]
- Abstract
The PhoP-PhoQ two-component system regulates the transcription of numerous genes in response to changes in extracellular divalent cation concentration and pH. Here we demonstrate that the Escherichia coli PhoP-PhoQ two-component system also responds to acetate. Signaling by the E. coli PhoP-PhoQ system was repressed during growth in acetate (> or = 25 mM) in a PhoQ-dependent manner. The periplasmic sensor domain of PhoQ was not required for acetate to repress signaling. Acetate-mediated repression of the PhoP-PhoQ system was not related to changes in the intracellular concentration of acetate metabolites such as acetyl-phosphate or acetyladenylate. Genetic analysis of acetate metabolism pathways suggested that a perturbation of acetyl coenzyme A turnover was the cause of decreased PhoP-PhoQ signaling during growth in acetate. Consistent with this hypothesis, intracellular acetyl coenzyme A levels rose during growth in the presence of exogenous acetate. Acetyl coenzyme A inhibited the autokinase activity of PhoQ in vitro, suggesting that the in vivo repressing effect may be due to a direct inhibition mechanism.