Serine phosphorylation regulates the P-type potassium pump KdpFABC

Marie E Sweet, Xihui Zhang, Hediye Erdjument-Bromage, Vikas Dubey, Himanshu Khandelia, Thomas A Neubert, Bjørn P Pedersen, David L Stokes*

*Corresponding author af dette arbejde

    Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review

    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.

    OriginalsprogEngelsk
    Artikelnummere55480
    TidsskrifteLife
    Vol/bind9
    Sider (fra-til)1-19
    Antal sider19
    ISSN2050-084X
    DOI
    StatusUdgivet - sep. 2020

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