Premium
Regulation of the epithelial sodium channel by specific palmitoyltransferases (DHHC) (860.6)
Author(s) -
Mukherjee Anindit,
Poland Paul,
Wang Zhijian,
Kleyman Thomas,
Hughey Rebecca
Publication year - 2014
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.28.1_supplement.860.6
Subject(s) - epithelial sodium channel , palmitoylation , xenopus , protein subunit , microbiology and biotechnology , chemistry , hek 293 cells , g alpha subunit , sodium channel , gamma subunit , biology , biochemistry , receptor , sodium , gene , enzyme , cysteine , organic chemistry
The epithelial sodium channel (ENaC) has a key role in the maintenance of extracellular fluid volume and control of blood pressure. ENaC is a member of the ENaC/degenerin family and is assembled with three structurally similar subunits (alpha, beta and gamma). We have shown that palmitoylation of specific cytoplasmic Cys residues in the beta and gamma subunits activate mouse ENaC by increasing channel open probability. In assessing channels that lack palmitoylation sites on the beta and/or gamma subunit, our data indicate that gamma subunit palmitoylation has a dominant role in activating ENaC. There is a family of 23 palmitolytransferases (referred to as DHHCs) in mice that catalyze the transfer of palmitate to cytoplasmic and transmembrane Cys in proteins. To directly assess the physiological significance of ENaC palmitoylation, we co‐expressed ENaC individually with all 23 palmitoyltransferases to identify specific palmitoyltransferases that can activate ENaC in Xenopus oocytes. We observed that five DHHCs significantly increased (1.8‐2.5 fold p < 0.05 ‐ 0.001) wild type channel activity. Co‐expression of these activating DHHCs with ENaC lacking Cys for either beta or gamma subunit palmitoylation revealed one DHHC with specificity for the gamma subunit. Using RT‐PCR we found that all five of the activating DHHC are present in mpkCCDc14 cells that express endogenous ENaC providing a model system to study regulation of ENaC palmitoylation. Results of our studies provide new insights regarding a regulatory pathway that has a large effect on the modulation of channel open probability. Grant Funding Source : supported by NIH 5R01DK065161‐09