Mechanisms of WNK1 and WNK4 interaction in the regulation of thiazide-sensitive NaCl cotransport

Yang, Chao-Ling; Zhu, Xiaoman; Wang, Zhaohong; Subramanya, Arohan R.; Ellison, David H.

doi:10.1172/jci200522452

Cited by 65 publications

(124 citation statements)

References 22 publications

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“…Long WNK1 physically interacts with WNK4 (35), which also stimulates endocytosis of ROMK (11). Thus, it is interesting to know whether WNK1 regulates ROMK1 synergistically with WNK4.…”

Section: Discussionmentioning

confidence: 99%

“…It has been shown that activation of ENaC by WNK1 requires the N-terminal amino acids 1-220 (15). Also, release of WNK4-mediated inhibition of Na-Cl cotransporter by WNK1 requires the kinase domain of WNK1 (35). Thus, it appears that hypertension in PHA II patients with WNK1 mutation is likely also caused by an increase in long WNK1, not KS-WNK1.…”

Section: Discussionmentioning

confidence: 99%

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Antagonistic regulation of ROMK by long and kidney-specific WNK1 isoforms

Lazrak

Liu

Huang³

2006

Proc. Natl. Acad. Sci. U.S.A.

160

207

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WNK kinases are serine-threonine kinases with an atypical placement of the catalytic lysine. Intronic deletions with increased expression of a ubiquitous long WNK1 transcript cause pseudohypoaldosteronism type 2 (PHA II), characterized by hypertension and hyperkalemia. Here, we report that long WNK1 inhibited ROMK1 by stimulating its endocytosis. Inhibition of ROMK by long WNK1 was synergistic with, but not dependent on, WNK4. A smaller transcript of WNK1 lacking the N-terminal 1-437 amino acids is expressed highly in the kidney. Whether expression of the KS-WNK1 (kidney-specific, KS) is altered in PHA II is not known. We found that KS-WNK1 did not inhibit ROMK1 but reversed the inhibition of ROMK1 caused by long WNK1. Consistent with the lack of inhibition by KS-WNK1, we found that amino acids 1-491 of the long WNK1 were sufficient for inhibiting ROMK. Dietary K ؉ restriction decreases ROMK abundance in the renal cortical-collecting ducts by stimulating endocytosis, an adaptative response important for conservation of K ؉ during K ؉ deficiency. We found that K ؉ restriction in rats increased whole-kidney transcript of long WNK1 while decreasing that of KS-WNK1. Thus, KS-WNK1 is a physiological antagonist of long WNK1. Hyperkalemia in PHA II patients with PHA II mutations may be caused, at least partially, by increased expression of long WNK1 with or without decreased expression of KS-WNK1. There are four mammalian WNK family members (1). WNK1, the first member identified, is Ͼ2,100 amino acids long (2). It contains an Ϸ270-aa kinase domain located near the amino terminus (e.g., amino acids 218-491 of the rat WNK1). WNK2, 3, and 4 are products of different genes and Ϸ1,200 to 1,600 amino acids in length (1, 2). The kinase domain of the four WNKs that share 85-90% sequence identity are unique in having the catalytic lysine located in the subdomain I instead of the conserved subdomain II of most protein kinases (1-3). Other conserved domains of WNK kinases include an autoinhibitory domain, 1-2 coiled-coil domains, and multiple PXXP prolinerich motifs for potential protein-protein interaction (1-4). Beyond the aforementioned conserved domains͞motifs, sequence identity among the four WNKs is much lower and few homologous regions exist.Pseudohypoaldosteronism type II (PHA II) is an autosomaldominant disease characterized by hypertension and hyperkalemia (5). Recently, Wilson et al. (6) reported that mutations of WNK1 and WNK4 cause PHA II. Mutations in the WNK1 gene are large deletions of the first intron leading to increased expression. Mutations in the WNK4 gene are missense mutations in the coding sequence outside the protein kinase domain. Several recent studies have examined the mechanisms for hypertension and hyperkalemia in PHA II patients. WNK4 inhibits the activity of the sodium chloride cotransporter. WNK4 mutants that cause disease fail to inhibit the sodium chloride cotransporter, suggesting that an increase in sodium chloride cotransporter activity in the distal convoluted tubule is a cause of hypertens...

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“…Long WNK1 physically interacts with WNK4 (35), which also stimulates endocytosis of ROMK (11). Thus, it is interesting to know whether WNK1 regulates ROMK1 synergistically with WNK4.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Antagonistic regulation of ROMK by long and kidney-specific WNK1 isoforms

Lazrak

Liu

Huang³

2006

Proc. Natl. Acad. Sci. U.S.A.

160

207

View full text Add to dashboard Cite

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“…T he WNK family of serine͞threonine kinases has been shown to function as important regulators of salt homeostasis (1)(2)(3)(4)(5)(6)(7)(8)(9). Mutations in the WNK4 or WNK1 genes cause a familial disorder [pseudohypoaldosteronism type II, (PHAII)] of diminished renal potassium excretion, excessive sodium retention, and hypertension (10).…”

mentioning

confidence: 99%

WNK1 kinase isoform switch regulates renal potassium excretion

Wade

Fang

Liu

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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121

138

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Members of the WNK family of serine͞threonine kinases have been implicated as important modulators of salt homeostasis, regulating the balance between renal sodium reabsorption and potassium excretion. Gain-of-expression mutations in the WNK1 gene uncouple Na ؉ and K ؉ balance and cause a familial disorder of diminished renal potassium excretion, excessive sodium retention, and hypertension (pseudohypoaldosteronism type II or Gordon's syndrome). Alternative splicing of the WNK1 gene produces a kidney-specific short form of WNK1 (KS-WNK1) and a more ubiquitous long form (L-WNK1), but it is not clear how either of these isoforms influence renal potassium excretion. Here we demonstrate that KS-WNK1 and L-WNK1 converge in a pathway to regulate the renal outermedullary K ؉ channel, Kir1.1. Reconstitution studies in Xenopus oocytes reveal that L-WNK1 significantly inhibits Kir1.1 by reducing cell surface localization of the channel.

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“…Our observation after immunofluorescence staining showed that normally NCC was mainly distributed on the Cos-7 cell membrane, with a small amount distributed in the cytoplasm ( Figure S2 in Supporting Information). WNK3 could increase the expression of NCC both on the membrane and in the cytoplasm of mammalian cells.Previous studies have indicated the amino terminal of WNK4 is the critical region in the regulation of NCC (Yang et al, 2005). Our present study found WNK3 (421-1800) fragment without the kinase domain had no effect on NCC at all while wild type WNK3 and WNK3 (1-420) fragment, containing the kinase domain, could increase NCC expression obviously.…”

mentioning

confidence: 40%

“…Previous studies have indicated the amino terminal of WNK4 is the critical region in the regulation of NCC (Yang et al, 2005). Our present study found WNK3 (421-1800) fragment without the kinase domain had no effect on NCC at all while wild type WNK3 and WNK3 (1-420) fragment, containing the kinase domain, could increase NCC expression obviously.…”

mentioning

confidence: 40%

WNK3 interacts with NCC

Wang

Pan

et al. 2016

Sci. China Life Sci.

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Dear Editor, NCC (Na-Cl cotransporter) is a cotransporter mainly distributed in the distal tubule of the kidney, functioning to reabsorb sodium and chloride ions from the tubular fluid into the cells of the renal distal convoluted tubule. It is a transmembrane protein belonging to the SLC12 cotransporter family of electro-neutral cation-coupled chloride cotransporters, which is closely related to hypertension (Gamba, 2005). A loss of NCC function can cause Gitelman syndrome, a disease characterized by low blood pressure, hypocalciuria, hypokalemic metabolic alkalosis, and hypomagnesemia, etc. WNK3 (With No Lysine K 3) is highly expressed in the whole length of the renal tubules (Glover et al., 2009). It was previously found to enhance the activity of NCC in Xenopus oocyte (Rinehart et al., 2005). Exploring the regulatory effect of WNK3 on NCC may be helpful to understand the occurrence of abnormal renal sodium transporters and provide new targets for the treatment of hypertension. However, whether WNK3 interacts directly with NCC in mammalian cells still remains unclear. In this article, we report the results of our co-immunoprecipitation experiments and confocal observations, confirming that WNK3 does interact with NCC and that the kinase domain of WNK3 plays an important role in the regulation of NCC.To explore whether there is reaction between WNK3 and NCC protein, Cos-7 cells were transfected by GFP-NCC with or without HA-WNK3 and co-immunoprecipitation experiments were performed 48 hours after transfection. As shown in Figure 1, anti-HA antibody with the presence of WNK3 immunoprecipitated NCC whereas serum with the absence of WNK3 did not, suggesting that the WNK3 protein interacts with NCC directly.In order to investigate the effect of WNK3 on NCC, HA-NCC was transfected into Cos-7 cells while increasing doses of HA-WNK3. Western-blot was carried out with anti-HA or anti-GAPDH antibodies 48 h later. The NCC protein expression level gradually increased with the increase of WNK3 dosage ( Figure S1 in Supporting Information). The expression of NCC and WNK3 was checked under a confocal fluorescent microscope ( Figure S2 in Supporting Information). The results showed that WNK3 increased NCC expression both on the cell membrane and in the cytoplasm. It has been confirmed that the enzyme region, the amino terminal, and/or the carboxyl terminal are the key elements of kinase activity. However, whether the enzyme region of WNK3 is necessary in regulating NCC is still unclear. We observed the changes of NCC expression after various WNK3 fragments were transferred into the cells. As shown in Figure S3 in Supporting Information, only the WNK3 fragments containing the enzyme region were able to increase the expression of NCC.WNK kinases belong to a subfamily of serine/threonine kinases. It was reported that the activity of NCC could be down-regulated by WNK4 (Moniz et al., 2010). Our study showed that in the mammalian cells WNK3 was also a chloride sensitive kinase to NCC expression, with its effect being the opposit...

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Mechanisms of WNK1 and WNK4 interaction in the regulation of thiazide-sensitive NaCl cotransport

Cited by 65 publications

References 22 publications

Antagonistic regulation of ROMK by long and kidney-specific WNK1 isoforms

Antagonistic regulation of ROMK by long and kidney-specific WNK1 isoforms

WNK1 kinase isoform switch regulates renal potassium excretion

WNK3 interacts with NCC

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