title: Hyperkalemic hypertension-associated cullin 3 promotes WNK signaling by degrading KLHL3.
abstract: Familial hyperkalemic hypertension (FHHt) is a monogenic disease resulting from mutations in genes encoding WNK kinases, the ubiquitin scaffold protein cullin 3 (CUL3), or the substrate adaptor kelch-like 3 (KLHL3). Disease-associated CUL3 mutations abrogate WNK kinase degradation in cells, but it is not clear how mutant forms of CUL3 promote WNK stability. Here, we demonstrated that an FHHt-causing CUL3 mutant (CUL3 Δ403-459) not only retains the ability to bind and ubiquitylate WNK kinases and KLHL3 in cells, but is also more heavily neddylated and activated than WT CUL3. In cells, activated CUL3 Δ403-459 depleted KLHL3, preventing WNK degradation, despite increased CUL3-mediated WNK ubiquitylation; therefore, CUL3 loss in kidney should phenocopy FHHt in murine models. As predicted, nephron-specific deletion of Cul3 in mice did increase WNK kinase levels and the abundance of phosphorylated Na-Cl cotransporter (NCC). Over time, however, Cul3 deletion caused renal dysfunction, including hypochloremic alkalosis, diabetes insipidus, and salt-sensitive hypotension, with depletion of sodium potassium chloride cotransporter 2 and aquaporin 2. Moreover, these animals exhibited renal inflammation, fibrosis, and increased cyclin E. These results indicate that FHHt-associated CUL3 Δ403-459 targets KLHL3 for degradation, thereby preventing WNK degradation, whereas general loss of CUL3 activity - while also impairing WNK degradation - has widespread toxic effects in the kidney.
authors.forename: James A
authors.initials: JA
authors.lastname: McCormick
authors.forename: Chao-Ling
authors.initials: CL
authors.lastname: Yang
authors.forename: Chong
authors.initials: C
authors.lastname: Zhang
authors.forename: Brittney
authors.initials: B
authors.lastname: Davidge
authors.forename: Katharina I
authors.initials: KI
authors.lastname: Blankenstein
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Terker
authors.forename: Bethzaida
authors.initials: B
authors.lastname: Yarbrough
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Meermeier
authors.forename: Hae J
authors.initials: HJ
authors.lastname: Park
authors.forename: Belinda
authors.initials: B
authors.lastname: McCully
authors.forename: Mark
authors.initials: M
authors.lastname: West
authors.forename: Aljona
authors.initials: A
authors.lastname: Borschewski
authors.forename: Nina
authors.initials: N
authors.lastname: Himmerkus
authors.forename: Markus
authors.initials: M
authors.lastname: Bleich
authors.forename: Sebastian
authors.initials: S
authors.lastname: Bachmann
authors.forename: Kerim
authors.initials: K
authors.lastname: Mutig
authors.forename: Eduardo R
authors.initials: ER
authors.lastname: Argaiz
authors.forename: Gerardo
authors.initials: G
authors.lastname: Gamba
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Singer
authors.forename: David H
authors.initials: DH
authors.lastname: Ellison
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D044842:Cullin Proteins / Q000235:genetics* / Q000502:physiology; D005260:Female; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D006973:Hypertension; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000378:metabolism / Q000473:pathology; D008297:Male; D018345:Mice, Knockout; D008840:Microfilament Proteins; D015778:Minor Histocompatibility Antigens; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D059748:Proteolysis; D011546:Pseudohypoaldosteronism / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D054875:Ubiquitination; D000076204:WNK Lysine-Deficient Protein Kinase 1; D014982:Xenopus laevis
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C503645:CUL3 protein, human; D002352:Carrier Proteins; D044842:Cullin Proteins; D047908:Intracellular Signaling Peptides and Proteins; C489837:KLHL3 protein, human; D008840:Microfilament 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