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A role for MARCKS in phosphoinositide‐dependent regulation of ENaC
Author(s) -
Alli Abdel A,
Bao HuiFang,
AlKhalili Otor,
Aldrugh Yasir,
Ma HePing,
Eaton Douglas C
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.860.2
Subject(s) - epithelial sodium channel , colocalization , microbiology and biotechnology , marcks , immunoprecipitation , phosphorylation , protein subunit , chemistry , confocal microscopy , apical membrane , protein kinase c , biology , biochemistry , membrane , sodium , organic chemistry , gene
Anionic phosphoinositides (i.e. PIP2 and PIP3) regulate the activity and protein expression of ENaC at the apical membrane. The mechanism by which anionic phosphoinositides are presented to ENaC is unknown. Here, we investigate the association between MARCKS, ENaC, and anionic phosphoinositides in vitro and in situ. Co‐immunoprecipitation experiments revealed a transient association between ENaC gamma subunit and MARCKS in a renal cell line (A6‐2F3). In overlay binding assays, recombinant GST‐MARCKS and GST‐ENaC beta subunit fusion proteins bound various phosphoinositides. Confocal microscopy confirmed the colocalization of MARCKS and PIP2 at the apical membrane of 2F3 cells. After treating 2F3 cells with PMA, immunoblot studies showed an increase in MARCKS phosphorylation, confocal microscopy experiments revealed displacement of MARCKS from the apical membrane, and transepithelial current decreased significantly. The findings presented here suggest a novel mechanism for the regulation of ENaC by phosphoinositides, but will require further investigation.