Regulation of activity and localization of the WNK1 protein kinase by hyperosmotic stress

Anna Zagórska, Eulalia Pozo-Guisado, Jérôme Boudeau, Alberto C. Vitari, Fatema H. Rafiqi, Jacob Thastrup, Maria Deak, David G. Campbell, Nick A. Morrice, Alan R. Prescott, Dario R. Alessi

    Research output: Contribution to journalArticlepeer-review

    160 Citations (Scopus)


    Mutations within the WNK1 (with-no-K[Lys] kinase-1) gene cause Gordon's hypertension syndrome. Little is known about how WNK1 is regulated. We demonstrate that WNK1 is rapidly activated and phosphorylated at multiple residues after exposure of cells to hyperosmotic conditions and that activation is mediated by the phosphorylation of its T-loop Ser382 residue, possibly triggered by a transautophosphorylation reaction. Activation of WNK1 coincides with the phosphorylation and activation of two WNK1 substrates, namely, the protein kinases STE20/SPS1-related proline alanine-rich kinase (SPAK) and oxidative stress response kinase-1 (OSR1). Small interfering RNA depletion of WNK1 impairs SPAK/OSR1 activity and phosphorylation of residues targeted by WNK1. Hyperosmotic stress induces rapid redistribution of WNK1 from the cytosol to vesicular structures that may comprise trans-Golgi network (TGN)/recycling endosomes, as they display rapid movement, colocalize with clathrin, adaptor protein complex 1 (AP-1), and TGN46, but not the AP-2 plasma membrane-coated pit marker nor the endosomal markers EEA1, Hrs, and LAMP1. Mutational analysis suggests that the WNK1 C-terminal noncatalytic domain mediates vesicle localization. Our observations shed light on the mechanism by which WNK1 is regulated by hyperosmotic stress.
    Original languageEnglish
    Pages (from-to)89-100
    Number of pages12
    JournalJournal of Cell Biology
    Issue number1
    Publication statusPublished - 1 Jan 2007


    • Amino Acid Sequence
    • Animals
    • Catalytic Domain
    • Cell Survival
    • Clathrin
    • Cytoplasmic Vesicles
    • Enzyme Activation
    • HeLa Cells
    • Humans
    • Intracellular Signaling Peptides and Proteins
    • Molecular Sequence Data
    • Osmotic Pressure
    • Phosphorylation
    • Phosphoserine
    • Protein Binding
    • Protein Transport
    • Protein-Serine-Threonine Kinases
    • Rats
    • Recombinant Fusion Proteins
    • Sorbitol
    • Transcription Factors


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