Angiotensin II signaling increases activity of the renal Na-Cl cotransporter through a WNK4-SPAK-dependent pathway

Pedro San-Cristobal, Diana Pacheco-Alvarez, Ciaran Richardson, Aaron M. Ring, Norma Vazquez, Fatema H. Rafiqi, Divya Chari, Kristopher T. Kahle, Qiang Leng, Norma A. Bobadilla, Steven C. Hebert, Dario R. Alessi, Richard P. Lifton, Gerardo Gamba

    Research output: Contribution to journalArticlepeer-review

    205 Citations (Scopus)


    Mutations in the kinase WNK4 cause pseudohypoaldosteronism type II (PHAII), a syndrome featuring hypertension and high serum K+ levels (hyperkalemia). WNK4 has distinct functional states that regulate the balance between renal salt reabsorption and K+ secretion by modulating the activities of renal transporters and channels, including the Na-Cl cotransporter NCC and the K+ channel ROMK. WNK4's functions could enable differential responses to intravascular volume depletion (hypovolemia) and hyperkalemia. Because hypovolemia is uniquely associated with high angiotensin II (AngII) levels, AngII signaling might modulate WNK4 activity. We show that AngII signaling in Xenopus oocytes increases NCC activity by abrogating WNK4's inhibition of NCC but does not alter WNK4's inhibition of ROMK. This effect requires AngII, its receptor AT1R, and WNK4, and is prevented by the AT1R inhibitor losartan. NCC activity is also increased by WNK4 harboring mutations found in PHAII, and this activity cannot be further augmented by AngII signaling, consistent with PHAII mutations providing constitutive activation of the signaling pathway between AT1R and NCC. AngII's effect on NCC is also dependent on the kinase SPAK because dominant-negative SPAK or elimination of the SPAK binding motif in NCC prevent activation of NCC by AngII signaling. These effects extend to mammalian cells. AngII increases phosphorylation of specific sites on SPAK and NCC that are necessary for activation of each in mpkDCT cells. These findings place WNK4 in the signaling pathway between AngII and NCC, and provide a mechanism by which hypovolemia maximizes renal salt reabsoprtion without concomitantly increasing K+ secretion.

    Original languageEnglish
    Pages (from-to)4384-4389
    Number of pages6
    JournalProceedings of the National Academy of Sciences of the United States of America
    Issue number11
    Early online date24 Feb 2009
    Publication statusPublished - 17 Mar 2009


    • Angiotensin II receptor
    • Hypertension
    • Distal convoluted tubule
    • Salt reabsorption
    • Thiazide


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