title: Properties of WNK1 and implications for other family members.
abstract: WNKs are large serine/threonine protein kinases structurally distinct from all other members of the protein kinase superfamily. Of the four human WNK family members, WNK1 and WNK4 have been linked to a hereditary form of hypertension, pseudohypoaldosteronism type II. We characterized the biochemical properties and regulation of WNK1 that may contribute to its physiological activities and abnormal function in disease. We showed that WNK1 is activated by hypertonic stress in kidney epithelial cells and in breast and colon cancer cell lines. In addition, hypotonic stress also led to a modest increase in WNK1 activity. Gel filtration suggested that WNK1 exists as a tetramer, and yeast two-hybrid data showed that the N terminus of WNK1 (residues 1-222) interacts with residues 481-660, which includes the WNK1 autoinhibitory domain and a C-terminal coiled-coil domain. Although cell biological studies have suggested a functional interaction between WNK1 and WNK4, we found no evidence of stable interactions between these kinases. However, WNK1 phosphorylated both WNK4 and WNK2. In addition, the WNK1 autoinhibitory domain inhibited the catalytic activity of these WNKs. These findings suggest potential mechanisms for interconnected regulation of WNK family members.
authors.affiliation: Department of Pharmacology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA.
authors.forename: Lisa Y
authors.initials: LY
authors.lastname: Lenertz
authors.forename: Byung-Hoon
authors.initials: BH
authors.lastname: Lee
authors.forename: Xiaoshan
authors.initials: X
authors.lastname: Min
authors.forename: Bing-e
authors.initials: BE
authors.lastname: Xu
authors.forename: Kyle
authors.initials: K
authors.lastname: Wedin
authors.forename: Svetlana
authors.initials: S
authors.lastname: Earnest
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Goldsmith
authors.forename: Melanie H
authors.initials: MH
authors.lastname: Cobb
mesh_terms: D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000473:pathology; D006801:Humans; D006973:Hypertension / Q000209:etiology; D007038:Hypotonic Solutions / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D015778:Minor Histocompatibility Antigens; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D017434:Protein Structure, Tertiary; D013312:Stress, Physiological / Q000378:metabolism; D000076204:WNK Lysine-Deficient Protein Kinase 1
chemical_list: D007038:Hypotonic Solutions; D047908:Intracellular Signaling Peptides and Proteins; D015778:Minor Histocompatibility Antigens; D017346:Protein Serine-Threonine Kinases; D000076204:WNK Lysine-Deficient Protein Kinase 1; C498743:WNK1 protein, human; C433806:WNK4 protein, human