Key result
Returning bacteria to a K+-rich environment inhibits the KdpFABC potassium pump via phosphorylation of Ser162 on KdpB, which abolishes the K+-dependence of ATP hydrolysis and blocks the catalytic cycle.
Why the study?
While transcriptional activation of bacterial KdpFABC expression is well studied, a mechanism for down-regulation when K+ levels are restored has not been described.
Design
In vitro experimental study
Authors
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Phosphorylation of KdpB Ser162 enables rapid KdpFABC down-regulation; leaves open conservation in eukaryotes and therapeutic targeting potential.
Serine phosphorylation of KdpB at Ser162 inhibits the KdpFABC potassium pump when bacteria return to a potassium-rich environment, revealing a unique regulatory mechanism for bacterial potassium homeostasis.
Sweet et al. (2020) studied this question. Potassium-rich environment (K+ shock) vs. Potassium-deficient environment was evaluated on ATPase activity and K+ transport inhibition. Returning bacteria to a K+-rich environment inhibits the KdpFABC potassium pump via phosphorylation of Ser162 on KdpB, which abolishes the K+-dependence of ATP hydrolysis and blocks the catalytic cycle.
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