Regulation of stability and function of the epithelial Na+ channel (ENaC) by ubiquitination

Details

Serval ID
serval:BIB_E11C8CEB1B1B
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Regulation of stability and function of the epithelial Na+ channel (ENaC) by ubiquitination
Journal
EMBO Journal
Author(s)
Staub  O., Gautschi  I., Ishikawa  T., Breitschopf  K., Ciechanover  A., Schild  L., Rotin  D.
ISSN
0261-4189 (Print)
Publication state
Published
Issued date
11/1997
Volume
16
Number
21
Pages
6325-36
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Nov 3
Abstract
The epithelial Na+ channel (ENaC), composed of three subunits (alpha beta gamma), plays a critical role in salt and fluid homeostasis. Abnormalities in channel opening and numbers have been linked to several genetic disorders, including cystic fibrosis, pseudohypoaldosteronism type I and Liddle syndrome. We have recently identified the ubiquitin-protein ligase Nedd4 as an interacting protein of ENaC. Here we show that ENaC is a short-lived protein (t1/2 approximately 1 h) that is ubiquitinated in vivo on the alpha and gamma (but not beta) subunits. Mutation of a cluster of Lys residues (to Arg) at the N-terminus of gamma ENaC leads to both inhibition of ubiquitination and increased channel activity, an effect augmented by N-terminal Lys to Arg mutations in alpha ENaC, but not in beta ENaC. This elevated channel activity is caused by an increase in the number of channels present at the plasma membrane; it represents increases in both cell-surface retention or recycling of ENaC and incorporation of new channels at the plasma membrane, as determined by Brefeldin A treatment. In addition, we find that the rapid turnover of the total pool of cellular ENaC is attenuated by inhibitors of both the proteasome and the lysosomal/endosomal degradation systems, and propose that whereas the unassembled subunits are degraded by the proteasome, the assembled alpha beta gamma ENaC complex is targeted for lysosomal degradation. Our results suggest that ENaC function is regulated by ubiquitination, and propose a paradigm for ubiquitination-mediated regulation of ion channels.
Keywords
Acetylcysteine/analogs & derivatives/pharmacology Amino Acid Sequence Animals Brefeldin A Calcium-Binding Proteins/*metabolism Cell Line Chloroquine/pharmacology Cyclopentanes/pharmacology Cysteine Endopeptidases/metabolism Dogs Endosomes/metabolism Epithelial Sodium Channel Epithelium/*metabolism Half-Life Ion Channel Gating/*physiology Ion Transport *Ligases Lysosomes/metabolism Molecular Sequence Data Multienzyme Complexes/metabolism Mutagenesis, Site-Directed Mutation Nuclear Magnetic Resonance, Biomolecular Oocytes Point Mutation Protease Inhibitors/pharmacology Proteasome Endopeptidase Complex Protein Conformation *Protein Processing, Post-Translational Rats Recombinant Fusion Proteins/metabolism Sodium/*metabolism Sodium Channels/*physiology Transfection *Ubiquitin-Protein Ligases Ubiquitins/*physiology Up-Regulation/physiology Xenopus laevis
Pubmed
Web of science
Open Access
Yes
Create date
24/01/2008 13:55
Last modification date
20/08/2019 17:05
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