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Vasopressin independent trafficking of aquaporin‐2 by prostaglandin E2
Author(s) -
Olesen Emma Tina Bisgaard,
Moeller Hanne Bjerregaard,
Nielsen Søren,
Frøkiær Jørgen,
Praetorius Helle A.,
Fenton Robert Andrew
Publication year - 2010
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.24.1_supplement.610.3
Subject(s) - aquaporin 2 , aquaporin 3 , vasopressin , phosphorylation , stimulation , receptor , prostaglandin e2 , endocrinology , chemistry , medicine , prostaglandin , microbiology and biotechnology , biology , aquaporin , biochemistry , mechanical engineering , water channel , engineering , inlet
Trafficking of aquaporin‐2 (AQP2) to the apical plasma membrane (APM) of principal cells in the renal collecting duct is predominantly regulated by vasopressin (VP). We investigated whether prostaglandin E2 (PGE2) could regulate AQP2 trafficking via an alternative VP independent mechanism. In vitro studies were performed using MDCK cells stably transfected with either wild type AQP2 (WT) or a mutated form where serine‐256 is substituted with alanine (S256A) and therefore cannot be phosphorylated. To analyze APM abundance of AQP2 we used both a biochemical approach based on biotin cell surface protein labeling and immunocytochemistry. Compared to controls, 40 minutes of PGE2 (10 −7 M) increased APM abundance of AQP2 in WT cells, but not in S256A cells. Varying PGE2 concentrations, from 10 −10 M to 10 −6 M, resulted in a gradual increase in AQP2 APM abundance. A time course study of PGE2 stimulation for 5 to 120 minutes revealed that APM abundance of AQP2 increased until 80 minutes and that this effect was sustained at 120 minutes. AQP2 S256 phosphorylation increased after 40 min of PGE2 stimulation. The prostanoid receptor 4 (EP4) antagonist AH23848, 30μM, attenuated, but did not completely abolish the effect of PGE2 on AQP2 trafficking. We conclude that PGE2 induces trafficking and S256 phosphorylation of AQP2 and that trafficking may be mediated, at least in part, by the EP4 receptor.