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Proc Natl Acad Sci U S A. 2014 Oct 28;111(43):15556-61. doi: 10.1073/pnas.1418342111. Epub 2014 Oct 13.

Angiotensin II signaling via protein kinase C phosphorylates Kelch-like 3, preventing WNK4 degradation.

Author information

1
Departments of Genetics and Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo 173-8605, Japan; and Department of Clinical Epigenetics, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-0041, Japan Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510; richard.lifton@yale.edu shigeru.shibata@med.teikyo-u.ac.jp.
2
Departments of Genetics and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510;
3
Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo 173-8605, Japan; and.
4
Molecular Biophysics and Biochemistry and.
5
Departments of Genetics and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510; richard.lifton@yale.edu shigeru.shibata@med.teikyo-u.ac.jp.

Abstract

Hypertension contributes to the global burden of cardiovascular disease. Increased dietary K(+) reduces blood pressure; however, the mechanism has been obscure. Human genetic studies have suggested that the mechanism is an obligatory inverse relationship between renal salt reabsorption and K(+) secretion. Mutations in the kinases with-no-lysine 4 (WNK4) or WNK1, or in either Cullin 3 (CUL3) or Kelch-like 3 (KLHL3)--components of an E3 ubiquitin ligase complex that targets WNKs for degradation--cause constitutively increased renal salt reabsorption and impaired K(+) secretion, resulting in hypertension and hyperkalemia. The normal mechanisms that regulate the activity of this ubiquitin ligase and levels of WNKs have been unknown. We posited that missense mutations in KLHL3 that impair binding of WNK4 might represent a phenocopy of the normal physiologic response to volume depletion in which salt reabsorption is maximized. We show that KLHL3 is phosphorylated at serine 433 in the Kelch domain (a site frequently mutated in hypertension with hyperkalemia) by protein kinase C in cultured cells and that this phosphorylation prevents WNK4 binding and degradation. This phosphorylation can be induced by angiotensin II (AII) signaling. Consistent with these in vitro observations, AII administration to mice, even in the absence of volume depletion, induces renal KLHL3(S433) phosphorylation and increased levels of both WNK4 and the NaCl cotransporter. Thus, AII, which is selectively induced in volume depletion, provides the signal that prevents CUL3/KLHL3-mediated degradation of WNK4, directing the kidney to maximize renal salt reabsorption while inhibiting K(+) secretion in the setting of volume depletion.

KEYWORDS:

PHAII; distal tubule; hypertension; posttranslational modification; renin–angiotensin–aldosterone system

PMID:
25313067
PMCID:
PMC4217463
DOI:
10.1073/pnas.1418342111
[Indexed for MEDLINE]
Free PMC Article

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