Carboxylmethylation of the β Subunit of xENaC Regulates Channel Activity

• DOI: 10.1074/jbc.273.44.28746
• Publication Date: 2002-07-26T15:13:03Z
• Authors: Michael D. Rokaw; Jun-Min Wang; Robert S. Edinger; Ora A. Weisz; Daniel Hui; Pamela Middleton; Vadim Shlyonsky; Bakhrom K. Berdiev; Iskander Ismailov; Douglas C. Eaton; Dale J. Benos; John P. Johnson
• Keywords: Electrophoresis; 0301 basic medicine; Polyacrylamide Gel; Lipid Bilayers; Sciences bio-médicales et agricoles; Sodium Channels -- immunology -- metabolism; Methylation; Antibodies; Sodium Channels; Cell Line; 03 medical and health sciences; Aldosterone -- pharmacology; Antibodies -- immunology; Electrophoresis, Polyacrylamide Gel; Amino Acid Sequence; Aldosterone

The action of aldosterone to increase apical membrane permeability in responsive epithelia is thought be due activation sodium channels. Aldosterone stimulates methylation a 95-kDa protein A6 cells, and we have previously shown that the immunopurified Na⁺ channel complex increases open probability these channels planar lipid bilayers. We report here carboxylmethylation β subunit xENaC cells. <i>In vitro</i> translated subunit, but not α or γ, serves as substrate for carboxylmethylation. Carboxylmethylation ENaC reconstituted bilayers leads an only when present. When immunoprecipitated from cells analyzed by Western blot with antibodies three subunits xENaC, all are recognized constituents complex. results suggest activity regulated, part, xENaC.