Characterisation of the Cullin-3 mutation that causes a severe form of familial hypertension and hyperkalaemia.
Deletion of exon 9 from Cullin-3 (CUL3, residues 403-459: CUL3(Δ403-459)) 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, CUL3(Δ403-459), is severely compromised in its ability to ubiquitylate WNKs, possibly due to altered structural flexibility. Instead, CUL3(Δ403-459) auto-ubiquitylates and loses interaction with two important Cullin regulators: the COP9-signalosome and CAND1. A novel knock-in mouse model of CUL3(WT) (/Δ403-459) 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.
MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK francesrose.schumacher@gmail.com kmo22@medschl.cam.ac.uk t.kurz@dundee.ac.uk.
Frances-Rose
FR
Schumacher
Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK.
Keith
K
Siew
MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK.
Jinwei
J
Zhang
MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK.
Clare
C
Johnson
MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK.
Nicola
N
Wood
Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK.
Sarah E
SE
Cleary
Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK.
Raya S
RS
Al Maskari
Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK.
James T
JT
Ferryman
Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK.
Iris
I
Hardege
Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK.
Yasmin
Division of Cardiovascular Medicine, Department of Medicine, University of Cambridge, Cambridge, UK.
Nichola L
NL
Figg
Institute of Biochemistry, ETH Zürich, Zürich, Switzerland.
Radoslav
R
Enchev
MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK.
Axel
A
Knebel
Division of Experimental Medicine and Immunotherapeutics, University of Cambridge, Cambridge, UK francesrose.schumacher@gmail.com kmo22@medschl.cam.ac.uk t.kurz@dundee.ac.uk.
Kevin M
KM
O'Shaughnessy
MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee, UK francesrose.schumacher@gmail.com kmo22@medschl.cam.ac.uk t.kurz@dundee.ac.uk.
Thimo
T
Kurz
D000818:Animals; D044842:Cullin Proteins / Q000235:genetics* / Q000378:metabolism; D004195:Disease Models, Animal; D057809:HEK293 Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011546:Pseudohypoaldosteronism / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology
C503645:CUL3 protein, human; D044842:Cullin Proteins; D047908:Intracellular Signaling Peptides and Proteins; D017346:Protein Serine-Threonine Kinases
CUL3; WNK/SPAK/OSR1 pathway; cullin; monogenic hypertension syndromes; proteasome; ubiquitin