Solution Structure of the WNK1 Autoinhibitory Domain, a WNK-Specific PF2 Domain.
Moon, T.M., Correa, F., Kinch, L.N., Piala, A.T., Gardner, K.H., Goldsmith, E.J.(2013) J Mol Biol 425: 1245-1252
- PubMed: 23376100 
- DOI: https://doi.org/10.1016/j.jmb.2013.01.031
- Primary Citation of Related Structures:  
2LRU - PubMed Abstract: 
WNK1 [with no lysine (K)-1] is a 250-kDa serine/threonine protein kinase involved in the maintenance of cellular salt levels and is directly linked to a hereditary form of hypertension. Here, we report the solution NMR structure of the autoinhibitory domain of WNK1 (WNK1-AI), a small regulatory subunit that lies immediately C-terminal of the kinase domain. We show that this domain is a homolog of the RFXV-binding PASK/FRAY homology 2 (PF2) domain found in OSR (oxidative stress responsive) and SPAK (serine/threonine proline-alanine-rich) kinases, which are substrates of WNK1. The WNK1-AI has a circularly permuted topology relative to the OSR1-PF2 domain. Nevertheless, like PF2 domains, WNK1-AI binds peptides that contain an RFXV motif with micromolar affinities as assessed by changes in (1)H,(15)N heteronuclear single quantum coherence spectra. Mutations to the WNK1-AI and binding peptides confirm a similar binding mode.
Organizational Affiliation: 
Department of Pharmacology, College of Medicine, University of Vermont, 89 Beaumont Avenue, Burlington, VT 05405, USA. thomas.moon@uvm.edu