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Role of SPAK in short term activation of kidney electroneutral cation‐Cl − ‐cotransporters by vasopressin
Author(s) -
Saritas Turgay,
Ellison David,
McCormick James,
Delpire Eric,
Borschewski Aljona,
Palige Alex,
Uchida Shinichi,
Bachmann Sebastian,
Mutig Kerim
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1038.21
Subject(s) - phosphorylation , medicine , endocrinology , cotransporter , vasopressin , chemistry , knockout mouse , autophosphorylation , agonist , kinase , receptor , biology , biochemistry , protein kinase a , sodium , organic chemistry
Aim of the present study was to elucidate the role of the sterile 20/SPS1‐related proline/alanine‐rich kinase (SPAK) during the vasopressin‐induced phosphorylation of the renal Na+,K+,Cl − ‐ (NKCC2) and Na+,Cl − ‐ (NCC) cotransporters. To this end adult SPAK‐knockout mice and wildtype mice (WT) were treated with the vasopressin V2 receptor agonist desmopressin (dDAVP, 1ng/kg bodyweight, 30 min) or vehicle. Abundance and localization of total and phosphorylated NKCC2 and NCC were determined by Western blot, immunofluorescence labelling and immunoelectron microscopy. During steady state SPAK −/− mice showed markedly increased levels of phosphorylated NKCC2 (+320±40% vs. controls, p < .05) whereas total NKCC2 levels were unchanged. Levels of total and of phosphorylated NCC were reduced (−72±18% for NCC, −58±13% for pS71‐NCC vs. controls, p <.05). dDAVP treatment significantly increased SPAK phosphorylation at S383 in WT mice (+89±32% vs. controls, p < .05) and NKCC2 phosphorylation to a similar extent in WT (+55% ) and SPAK−/− mice (+55%). In contrast, dDAVP‐induced increases of NCC phosphorylation were only detectable in WT (+86% for pS71‐NCC and +163% for pT53‐NCC) but not in SPAK−/− mice. In conclusion, this study provides in‐vivo evidence for divergent roles of SPAK in TAL and DCT. Work was supported by the German Research Foundation (FOR667).