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Micro RNA 802 (Mir‐802) stimulates ROMK channels by suppressing caveolin‐1 expression during a high potassium (K) intake
Author(s) -
Lin Daohong,
Yue Peng,
Pan Chunyang,
Sun Peng,
Wang Wenhui
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.626.1
Subject(s) - hek 293 cells , chemistry , potassium channel , microbiology and biotechnology , transfection , western blot , medicine , endocrinology , biology , biochemistry , receptor , gene
The aim of the present study is to examine the role of Mir‐802 in mediating the effect of a high K intake on ROMK channel activity. Northern blot analysis demonstrated that a high K intake stimulated the Mir‐802 transcription in the mouse kidney. Expression of Mir‐802 decreased caveolin‐1 expression in both mouse collecting duct‐ and HEK cells. In contrast, suppression of endogenous Mir‐802 increased caveolin‐1 protein expression. Immunocytochemistry staining shows that caveolin‐1 and ROMK channels are co‐localized in the collecting duct. Moreover, gradient sucrose centrifuge revealed that ROMK proteins and caveolin‐1 were in the same layer. Also, caveolin‐1 is immunoprecipitated with ROMK and its N terminus was required for the interaction. Biotin labeling assay demonstrated that expression of caveolin‐1 decreased the ROMK1 expression in plasma membrane of HEK293 cells transfected with GFP‐ROMK1. In contrast, deletion of two putative caveolin‐1 binding sides ( 62 F I F FVDI W 69 , 77 W R Y KMTV F 84 , 93 F L F GLLW Y 100 ) increased the surface expression of ROMK1 channels. Finally, whole cell patch‐clamp experiments demonstrated that expression of Mir‐802 increased while overexpression of caveolin‐1 decreased K current in HEK293 cells transfected with GFP‐ROMK1. We concluded that Mir‐802 plays an important role in stimulating ROMK channel activity by suppressing caveolin‐1 expression in response to a high K intake.