Water and chloride as allosteric inhibitors in WNK kinase osmosensing

• DOI: 10.7554/elife.88224
• Publication Date: 2023-10-23T20:52:14Z
• Authors: Liliana R Teixeira; Radha Akella; John M Humphreys; Haixia He; Elizabeth J Golds...
• Keywords: Protein kinase domain; Chloride channel

Osmotic stress and chloride regulate the autophosphorylation activity of WNK1 WNK3 kinase domains. The domain unphosphorylated (uWNK1) is an asymmetric dimer possessing water molecules conserved in multiple uWNK1 crystal structures. Conserved waters are present two networks, referred to here as networks 1 2 (CWN1 CWN2). Here, we show that PEG400 applied crystals dimeric induces de-dimerization. Both chloride-binding site disrupted by PEG400. CWN1 surrounded a cluster pan-WNK-conserved charged residues. mutagenized these charges WNK3, highly active WNK isoform domain, WNK1, best studied crystallographically. Mutation E314 Activation Loop (WNK3/E314Q WNK3/E314A, homologous WNK1/E388A) enhanced rate autophosphorylation, reduced sensitivity. Other mutants coupled with greater sensitivity than wild-type. regulation thus appear linked. lower some may reflect effects on catalysis. Crystallography showed activating introduced conformational changes similar parts structure those induced mutations crystallography support role for inhibition consistent functioning allosteric ligand.