Serine phosphorylation regulates the P-type potassium pump KdpFABC
- NYU School of Medicine, United States
- University of Southern Denmark, Denmark
- Aarhus University, Denmark
Abstract
KdpFABC is an ATP-dependent K+ pump that ensures bacterial survival in K+-deficient environments. Whereas transcriptional activation of kdpFABC expression is well studied, a mechanism for down regulation when K+ levels are restored has not been described. Here we show that KdpFABC is inhibited when cells return to a K+-rich environment. The mechanism of inhibition involves phosphorylation of Ser162 on KdpB, which can be reversed in vitro by treatment with serine phosphatase. Mutating Ser162 to Alanine produces constitutive activity, whereas the phosphomimetic Ser162Asp mutation inactivates the pump. Analyses of the transport cycle show that serine phosphorylation abolishes the K+-dependence of ATP hydrolysis and blocks the catalytic cycle after formation of the aspartyl phosphate intermediate (E1~P). This regulatory mechanism is unique amongst P-type pumps and this study furthers our understanding of how bacteria control potassium homeostasis to maintain cell volume and osmotic potential.
Data availability
Raw mass spectrometry files have been deposited to the MassIVE database under accession code MSV000084906
Article and author information
Author details
Funding
National Institutes of Health (R01 GM108043)
- David L Stokes
National Institutes of Health (S10 RR027990)
- Thomas A Neubert
European Research Council (637372)
- Bjorn P Pedersen
Independent Research Fund Denmark (DFF-8021-00161)
- Bjorn P Pedersen
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Sweet et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Serine phosphorylation regulates the P-type potassium pump KdpFABC
eLife 9:e55480.
https://doi.org/10.7554/eLife.55480
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