Axon morphogenesis and maintenance require an evolutionary conserved safeguard function of Wnk kinases antagonizing Sarm and Axed

Kidneys play a central role in regulation of potassium homeostasis and maintenance of plasma K+ levels within a narrow physiological range. With-no-lysine (WNK) kinases, specifically WNK1 and WNK4, have been recognized to regulate K+ balance, in part, by orchestrating maxi K+ channel (BK)-dependent K+ secretion in the aldosterone-sensitive distal nephron (ASDN), which includes the connecting tubule and collecting duct. We recently demonstrated that the Ca2+-permeable TRPV4 channel is essential for BK activation in the ASDN. Furthermore, high K+ diet increases TRPV4 activity and expression largely in an aldosterone-dependent manner. In the current study, we aimed to test whether WNK kinases contribute to regulation of TRPV4 activity and its stimulation by aldosterone. Systemic inhibition of WNK with WNK463 (1 mg/kgBW for 3 days) markedly decreased TRPV4-dependent Ca2+ influx in freshly isolated split-opened collecting ducts. Aldosterone greatly increased TRPV4 activity and expression in cultured mpkCCDc14 cells and this effect was abolished in the presence of WNK463. Selective inhibition of WNK1 with WNK-in-11 (400 nM, 24 h) recapitulated the effects of WNK463 on TRPV4-dependent Ca2+ influx. Interestingly, WNK-in-11 did not interfere with up-regulation of TRPV4 expression by aldosterone, but prevented translocation of the channel to the apical plasma membrane. Furthermore, co-expression of TRPV4 and WNK1 into Chinese hamster ovary (CHO) cells increased the macroscopic TRPV4-dependent cation currents. In contrast, over-expression of TRPV4 with a dominant negative WNK1 variant (K233M) decreased the whole-cell currents, suggesting both stimulatory and permissive roles of WNK1 in regulation of TRPV4 activity. Overall, we show that WNK1 is essential for setting functional TRPV4 expression in the ASDN at the baseline and in response to aldosterone. We propose that this new mechanism contributes to regulation of K+ secretion and, by extension, urinary K+ levels to maintain systemic potassium homeostasis.

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WNK-SPAK/OSR1 signaling: lessons learned from an insect renal epithelium

AJP Renal Physiology ◽

10.1152/ajprenal.00176.2018 ◽

2018 ◽

Vol 315 (4) ◽

pp. F903-F907 ◽

Cited By ~ 5

Author(s):

Aylin R. Rodan

Keyword(s):

Ion Transport ◽

Calcium Binding ◽

Molecular Mechanisms ◽

Extracellular Volume ◽

Lessons Learned ◽

Renal Epithelium ◽

Dietary Potassium ◽

Wnk Kinases ◽

Cation Chloride Cotransporters

WNK [with no lysine (K)] kinases regulate renal epithelial ion transport to maintain homeostasis of electrolyte concentrations, extracellular volume, and blood pressure. The SLC12 cation-chloride cotransporters, including the sodium-potassium-2-chloride (NKCC) and sodium chloride cotransporters (NCC), are targets of WNK regulation via the intermediary kinases SPAK (Ste20-related proline/alanine-rich kinase) and OSR1 (oxidative stress response). The pathway is activated by low dietary potassium intake, resulting in increased phosphorylation and activity of NCC. Chloride regulates WNK kinases in vitro by binding to the active site and inhibiting autophosphorylation and has been proposed to modulate WNK activity in the distal convoluted tubule in response to low dietary potassium. WNK-SPAK/OSR1 regulation of NKCC-dependent ion transport is evolutionarily ancient, and it occurs in the Drosophila Malpighian (renal) tubule. Here, we review recent studies from the Drosophila tubule demonstrating cooperative roles for chloride and the scaffold protein Mo25 (mouse protein-25, also known as calcium-binding protein-39) in the regulation of WNK-SPAK/OSR1 signaling in a transporting renal epithelium. Insights gained from this genetically manipulable and physiologically accessible epithelium shed light on molecular mechanisms of regulation of the WNK-SPAK/OSR1 pathway, which is important in human health and disease.

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WNK1 Kinase Stimulates Angiogenesis to Promote Tumor Growth and Metastasis

Cancers ◽

10.3390/cancers12030575 ◽

2020 ◽

Vol 12 (3) ◽

pp. 575 ◽

Cited By ~ 4

Author(s):

Zong-Lin Sie ◽

Ruei-Yang Li ◽

Bonifasius Putera Sampurna ◽

Po-Jui Hsu ◽

Shu-Chen Liu ◽

...

Keyword(s):

Hepatoma Cells ◽

Transgenic Zebrafish ◽

Human Hepatoma Cells ◽

Vessel Formation ◽

Vegf Signaling ◽

Promote Tumor Growth ◽

Chemical Inhibitors ◽

Wnk Kinases ◽

Tumor Growth And Metastasis ◽

Endothelial Growth Factor

With-no-lysine (K)-1 (WNK1) is the founding member of family of four protein kinases with atypical placement of catalytic lysine that play important roles in regulating epithelial ion transport. Gain-of-function mutations of WNK1 and WNK4 cause a mendelian hypertension and hyperkalemic disease. WNK1 is ubiquitously expressed and essential for embryonic angiogenesis in mice. Increasing evidence indicates the role of WNK kinases in tumorigenesis at least partly by stimulating tumor cell proliferation. Here, we show that human hepatoma cells xenotransplanted into zebrafish produced high levels of vascular endothelial growth factor (VEGF) and WNK1, and induced expression of zebrafish wnk1. Knockdown of wnk1 in zebrafish decreased tumor-induced ectopic vessel formation and inhibited tumor proliferation. Inhibition of WNK1 or its downstream kinases OSR1 (oxidative stress responsive kinase 1)/SPAK (Ste20-related proline alanine rich kinase) using chemical inhibitors decreased ectopic vessel formation as well as proliferation of xenotransplanted hepatoma cells. The effect of WNK and OSR1 inhibitors is greater than that achieved by inhibitor of VEGF signaling cascade. These inhibitors also effectively inhibited tumorigenesis in two separate transgenic zebrafish models of intestinal and hepatocellular carcinomas. Endothelial-specific overexpression of wnk1 enhanced tumorigenesis in transgenic carcinogenic fish, supporting endothelial cell-autonomous effect of WNK1 in tumor promotion. Thus, WNK1 can promote tumorigenesis by multiple effects that include stimulating tumor angiogenesis. Inhibition of WNK1 may be a potent anti-cancer therapy.

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(WNK)ing at death: With-no-lysine (Wnk) kinases in neuropathies and neuronal survival

Brain Research Bulletin ◽

10.1016/j.brainresbull.2016.04.017 ◽

2016 ◽

Vol 125 ◽

pp. 92-98 ◽

Cited By ~ 5

Author(s):

Bor Luen Tang

Keyword(s):

Neuronal Survival ◽

Wnk Kinases

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WNK4 kinase is a negative regulator of K+-Cl− cotransporters

AJP Renal Physiology ◽

10.1152/ajprenal.00335.2006 ◽

2007 ◽

Vol 292 (4) ◽

pp. F1197-F1207 ◽

Cited By ~ 49

Author(s):

Tomas Garzón-Muvdi ◽

Diana Pacheco-Alvarez ◽

Kenneth B. E. Gagnon ◽

Norma Vázquez ◽

José Ponce-Coria ◽

...

Keyword(s):

Expression System ◽

Negative Regulator ◽

Cell Swelling ◽

Xenopus Laevis Oocytes ◽

Missense Mutations ◽

Phosphatase Inhibitors ◽

Membrane Transport Proteins ◽

Protein Phosphatase Inhibitors ◽

Pseudohypoaldosteronism Type Ii ◽

Wnk Kinases

WNK kinases [with no lysine (K) kinase] are emerging as regulators of several membrane transport proteins in which WNKs act as molecular switches that coordinate the activity of several players. Members of the cation-coupled chloride cotransporters family (solute carrier family number 12) are one of the main targets. WNK3 activates the Na+-driven cotransporters NCC, NKCC1, and NKCC2 and inhibits the K+-driven cotransporters KCC1 to KCC4. WNK4 inhibits the activity of NCC and NKCC1, while in the presence of the STE20-related proline-alanine-rich kinase SPAK activates NKCC1. Nothing is known, however, regarding the effect of WNK4 on the K+-Cl− cotransporters. Using the heterologous expression system of Xenopus laevis oocytes, here we show that WNK4 inhibits the activity of the K+-Cl− cotransporters KCC1, KCC3, and KCC4 under cell swelling, a condition in which these cotransporters are maximally active. The effect of WNK4 requires its catalytic activity because it was lost by the substitution of aspartate 318 for alanine (WNK4-D318A) that renders WNK4 catalytically inactive. In contrast, three different WNK4 missense mutations that cause pseudohypoaldosteronism type II do not affect the WNK4-induced inhibition of KCC4. Finally, we observed that catalytically inactive WNK4-D318A is able to bypass the tonicity requirements for KCC2 and KCC3 activation in isotonic conditions. This effect is enhanced by the presence of catalytically inactive SPAK, was prevented by the presence of protein phosphatase inhibitors, and was not present in KCC1 and KCC4. Our results reveal that WNK4 regulates the activity of the K+-Cl− cotransporters expressed in the kidney.

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Mechanism of regulation of renal ion transport by WNK kinases

Current Opinion in Nephrology & Hypertension ◽

10.1097/mnh.0b013e32830dd580 ◽

2008 ◽

Vol 17 (5) ◽

pp. 519-525 ◽

Cited By ~ 53

Author(s):

Chou-Long Huang ◽

Sung-Sen Yang ◽

Shih-Hua Lin

Keyword(s):

Ion Transport ◽

Wnk Kinases

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WNK kinases: molecular regulators of integrated epithelial ion transport

Current Opinion in Nephrology & Hypertension ◽

10.1097/00041552-200409000-00012 ◽

2004 ◽

Vol 13 (5) ◽

pp. 557-562 ◽

Cited By ~ 56

Author(s):

Kristopher T Kahle ◽

Frederick H Wilson ◽

Maria Lalioti ◽

Hakan Toka ◽

Hui Qin ◽

...

Keyword(s):

Ion Transport ◽

Epithelial Ion Transport ◽

Wnk Kinases

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Effects of potassium on expression of renal sodium transporters in salt-sensitive hypertensive rats induced by uninephrectomy

AJP Renal Physiology ◽

10.1152/ajprenal.00598.2010 ◽

2011 ◽

Vol 300 (6) ◽

pp. F1422-F1430 ◽

Cited By ~ 12

Author(s):

Ji Yong Jung ◽

Sejoong Kim ◽

Jay Wook Lee ◽

Eun Sook Jung ◽

Nam Ju Heo ◽

...

Keyword(s):

Experimental Period ◽

Urinary Sodium Excretion ◽

Systemic Blood Pressure ◽

Mixed Solution ◽

Sprague Dawley ◽

Sodium Transporters ◽

Sprague Dawley Rats ◽

Dietary Potassium ◽

Wnk Kinases ◽

Type 3

Dietary potassium is an important modulator of systemic blood pressure (BP). The purpose of this study was to determine whether dietary potassium is associated with an altered abundance of major renal sodium transporters that may contribute to the modulation of systemic BP. A unilateral nephrectomy (uNx) was performed in male Sprague-Dawley rats, and the rats were fed a normal-salt diet (0.3% NaCl) for 4 wk. Thereafter, the rats were fed a high-salt (HS) diet (3% NaCl) for the entire experimental period. The potassium-repleted (HS+KCl) group was given a mixed solution of 1% KCl as a substitute for drinking water. We examined the changes in the abundance of major renal sodium transporters and the expression of mRNA of With-No-Lysine (WNK) kinases sequentially at 1 and 3 wk. The systolic BP of the HS+KCl group was decreased compared with the HS group (140.3 ± 2.97 vs. 150.9 ± 4.04 mmHg at 1 wk; 180.3 ± 1.76 vs. 207.7 ± 6.21 mmHg at 3 wk). The protein abundances of type 3 Na+/H+ exchanger (NHE3) and Na+-Cl− cotransporter (NCC) in the HS+KCl group were significantly decreased (53 and 45% of the HS group at 1 wk, respectively; 19 and 8% of HS group at 3 wk). WNK4 mRNA expression was significantly increased in the HS+KCl group (1.4-fold of control at 1 wk and 1.9-fold of control at 3 wk). The downregulation of NHE3 and NCC may contribute to the BP-attenuating effect of dietary potassium associated with increased urinary sodium excretion.

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