WNK1 activates SGK1 by a phosphatidylinositol 3-kinase-dependent and non-catalytic mechanism

Bing E. Xu, Steve Stippec, Ahmed Lazrak, Chou Long Huang, Melanie H. Cobb

Research output: Contribution to journalArticlepeer-review

83 Scopus citations


WNK1 (with no lysine (K) 1) is a protein-serine/threonine kinase with a unique catalytic site organization. Deletions in the first intron of the WNK1 gene were found in a group of hypertensive patients with pseudohypoaldosteronism type II. No changes in coding sequence of WNK1 were found, but its expression was increased severalfold. We have been investigating actions of WNK1 and have found that WNK1 activates the serum- and glucocorticoid-induced protein kinase SGK1, which impacts membrane expression of the epithelial sodium channel. Here we explore the role of WNK1 in SGK1 regulation. Activation of SGK1 by WNK1 is blocked by phosphatidylinositol 3-kinase inhibitors. Neither the catalytic activity nor the kinase domain of WNK1 is required; rather the N-terminal 220 residues of WNK1 are necessary and sufficient to activate SGK1. Phosphorylation of WNK1 on Thr-58 contributes to SGK1 activation. Finally, we show that WNK1 is required for the activation of SGK1 by insulin-like growth factor 1.

Original languageEnglish (US)
Pages (from-to)34218-34223
Number of pages6
JournalJournal of Biological Chemistry
Issue number40
StatePublished - Oct 7 2005

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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