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Endosomal deubiquitinating enzyme (DUB) regulates apical recycling of epithelial Na + channels (ENaC)
Author(s) -
Butterworth Michael Bruce,
Edinger Robert S,
Ovaa Huib,
Johnson John P,
Frizzell Raymond A
Publication year - 2007
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.21.5.a536-b
Subject(s) - epithelial sodium channel , microbiology and biotechnology , nedd4 , ubiquitin , forskolin , chemistry , apical membrane , endocytosis , ubiquitin ligase , deubiquitinating enzyme , biology , cell , biochemistry , receptor , sodium , organic chemistry , gene , membrane
ENaC surface density in the cortical collecting duct (CCD) is established by regulated insertion and retrieval at the apical membrane and recycling of internalized ENaC. Nedd4‐2 ligase‐dependent ubiquitylation elicits its endocytosis and proteosomal degradation. Apical ENaC recycling therefore implicates DUBs. Using a chemical probe approach we identified ubiquitin carboxy‐terminal hydrolase (UCH‐L3) as the predominant DUB in vesicular endocytic and recycling compartments in mouse CCD. ENaC currents in Xenopus oocytes were reduced 91±2% by Nedd4‐2 co‐expression which was completely reversed with co‐expression of UCH‐L3. Inhibition of UCH in filter‐cultured CCD cells resulted in a rapid decline in ENaC currents which was accelerated by forskolin stimulation, suggesting that UCH is responsible for recycling ENaC to the apical surface. Knock down of UCH‐L3 reduced both basal and cAMP‐stimulated ENaC currents. These results identify UCH‐L3 as the predominant DUB in the regulation of ENaC recycling and cell surface density in CCD cells. Support (CFF BUTTER06G0, NIH DK54814, DK072506 , DK 57718, DK54814)