TY - JOUR
T1 - Kidney-specific WNK1 isoform (KS-WNK1) is a potent activator of WNK4 and NCC
AU - Argaiz, Eduardo R.
AU - Chavez-Canales, Maria
AU - Ostrosky-Frid, Mauricio
AU - Rodríguez-Gama, Alejandro
AU - Vázquez, Norma
AU - Gonzalez-Rodriguez, Xochiquetzal
AU - Garcia-Valdes, Jesus
AU - Hadchouel, Juliette
AU - Ellison, David
AU - Gamba, Gerardo
N1 - Funding Information:
Because KS-WNK1 lacks the kinase domain, it cannot phosphorylate and activate the intermediary kinases SPAK and OSR1 directly. Instead, NCC activation might result from interaction with, and activation of, endogenous WNK in the oocyte. This is supported by the observation that elimination of
Funding Information:
This work was supported by the collaborative grant no. 188712 from CONACyT (Mexico) and ANR-12-ISVS1-0001-01 (France) to G. Gamba and J. Hadchouel, the grant IN207716 from DGAPA, UNAM to G. Gamba, and the NIDDK RO1 grant no. DK051496-15 to D. Ellison, G, Gamba, and J. Hadchouel.
Funding Information:
We thank Dario Alessi for the kind gift of WNK468 inhibitor. E. Argaiz was supported by a scholarship from CONACyT-Mexico and is a graduate student in the Doctorado en Ciencias Biomédicas program of the Universidad Nacional Autónoma de México.
Publisher Copyright:
© 2018 American Physiological Society. All rights reserved.
PY - 2018/9/6
Y1 - 2018/9/6
N2 - Familial hyperkalemic hypertension (FHHt) can be mainly attributed to increased activity of the renal Na+:Cl- cotransporter (NCC), which is caused by altered expression and regulation of the with-no-lysine (K) 1 (WNK1) or WNK4 kinases. The WNK1 gene gives rise to a kidney-specific isoform that lacks the kinase domain (KS-WNK1), the expression of which occurs primarily in the distal convoluted tubule. The role played by KS-WNK1 in the modulation of the WNK/STE20-proline-alanine rich kinase (SPAK)/ NCC pathway remains elusive. In the present study, we assessed the effect of human KS-WNK1 on NCC activity and on the WNK4-SPAK pathway. Microinjection of oocytes with human KS-WNK1 cRNA induces remarkable activation and phosphorylation of SPAK and NCC. The effect of KS-WNK1 was abrogated by eliminating a WNK-WNK-interacting domain and by a specific WNK inhibitor, WNK463, indicating that the activation of SPAK/NCC by KS-WNK1 is due to interaction with another WNK kinase. Under control conditions in oocytes, the activating serine 335 of the WNK4 T loop is not phosphorylated. In contrast, this serine becomes phosphorylated when the intracellular chloride concentration ([Cl-]i) is reduced or when KS-WNK1 is coexpressed with WNK4. KS-WNK1-mediated activation of WNK4 is not due to a decrease of the [Cl-]i. Coimmunoprecipitation analysis revealed that KS-WNK1 and WNK4 interact with each other and that WNK4 becomes autophosphorylated at serine 335 when it is associated with KS-WNK1. Together, these observations suggest that WNK4 becomes active in the presence of KS-WNK1, despite a constant [Cl-]i.
AB - Familial hyperkalemic hypertension (FHHt) can be mainly attributed to increased activity of the renal Na+:Cl- cotransporter (NCC), which is caused by altered expression and regulation of the with-no-lysine (K) 1 (WNK1) or WNK4 kinases. The WNK1 gene gives rise to a kidney-specific isoform that lacks the kinase domain (KS-WNK1), the expression of which occurs primarily in the distal convoluted tubule. The role played by KS-WNK1 in the modulation of the WNK/STE20-proline-alanine rich kinase (SPAK)/ NCC pathway remains elusive. In the present study, we assessed the effect of human KS-WNK1 on NCC activity and on the WNK4-SPAK pathway. Microinjection of oocytes with human KS-WNK1 cRNA induces remarkable activation and phosphorylation of SPAK and NCC. The effect of KS-WNK1 was abrogated by eliminating a WNK-WNK-interacting domain and by a specific WNK inhibitor, WNK463, indicating that the activation of SPAK/NCC by KS-WNK1 is due to interaction with another WNK kinase. Under control conditions in oocytes, the activating serine 335 of the WNK4 T loop is not phosphorylated. In contrast, this serine becomes phosphorylated when the intracellular chloride concentration ([Cl-]i) is reduced or when KS-WNK1 is coexpressed with WNK4. KS-WNK1-mediated activation of WNK4 is not due to a decrease of the [Cl-]i. Coimmunoprecipitation analysis revealed that KS-WNK1 and WNK4 interact with each other and that WNK4 becomes autophosphorylated at serine 335 when it is associated with KS-WNK1. Together, these observations suggest that WNK4 becomes active in the presence of KS-WNK1, despite a constant [Cl-]i.
KW - Distal convoluted tubule
KW - Diuretics
KW - Na:Cl cotransporter
KW - STE20-proline-alanine rich kinase
KW - Salt transport
UR - http://www.scopus.com/inward/record.url?scp=85051144127&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85051144127&partnerID=8YFLogxK
U2 - 10.1152/ajprenal.00145.2018
DO - 10.1152/ajprenal.00145.2018
M3 - Article
C2 - 29846116
AN - SCOPUS:85051144127
VL - 315
SP - F734-F745
JO - American journal of physiology. Renal physiology
JF - American journal of physiology. Renal physiology
SN - 0363-6127
IS - 3
ER -