Characterisation of the Cullin-3 mutation that causes a severe form of familial hypertension and hyperkalaemia

Frances-Rose Schumacher, Keith Siew, Jinwei Zhang, Clare Johnson, Nicola Wood, Sarah E Cleary, Raya S Al Maskari, James T Ferryman, Iris Hardege, [No Value] Yasmin, Nichola L Figg, Radoslav Enchev, Axel Knebel, Kevin M O'Shaughnessy, Thimo Kurz

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48 Citations (Scopus)
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Abstract

Deletion of exon 9 from Cullin-3 (CUL3, residues 403-459: CUL3Δ403-459) causes pseudohypoaldosteronism type IIE (PHA2E), a severe form of familial hyperkalaemia and hypertension (FHHt). CUL3 binds the RING protein RBX1 and various substrate adaptors to form Cullin-RING-ubiquitin-ligase complexes. Bound to KLHL3, CUL3-RBX1 ubiquitylates WNK kinases, promoting their ubiquitin-mediated proteasomal degradation. Since WNK kinases activate Na/Cl co-transporters to promote salt retention, CUL3 regulates blood pressure. Mutations in both KLHL3 and WNK kinases cause PHA2 by disrupting Cullin-RING-ligase formation. We report here that the PHA2E mutant, CUL3Δ403-459, is severely compromised in its ability to ubiquitylate WNKs, possibly due to altered structural flexibility. Instead, CUL3Δ403-459 auto-ubiquitylates and loses interaction with two important Cullin regulators: the COP9-signalosome and CAND1. A novel knock-in mouse model of CUL3WTΔ403-459 closely recapitulates the human PHA2E phenotype. These mice also show changes in the arterial pulse waveform, suggesting a vascular contribution to their hypertension not reported in previous FHHt models. These findings may explain the severity of the FHHt phenotype caused by CUL3 mutations compared to those reported in KLHL3 or WNK kinases.

Original languageEnglish
Pages (from-to)1285-1306
Number of pages22
JournalEmbo Molecular Medicine
Volume7
Issue number10
Early online date18 Aug 2015
DOIs
Publication statusPublished - 1 Oct 2015

Keywords

  • CUL3
  • Cullin
  • Monogenic hypertension syndromes
  • Proteasome
  • Ubiquitin
  • WNK/SPAK/OSR1 pathway

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