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Type: Journal article
Title: Roles of the C termini of α-, β-, and γ-subunits of epithelial Na⁺ channels (ENaC) in regulating ENaC and mediating its inhibition by cytosolic Na⁺
Other Titles: Roles of the C termini of alpha-, beta-, and gamma-subunits of epithelial Na(+) channels (ENaC) in regulating ENaC and mediating its inhibition by cytosolic Na(+)
Author: Dinudom, A.
Harvey, K.
Komwatanat, P.
Jolliffe, C.
Young, J.
Kumar, S.
Cook, D.
Citation: Journal of Biological Chemistry, 2001; 276(17):13744-13749
Publisher: Amer Soc Biochemistry Molecular Biology Inc
Issue Date: 2001
ISSN: 0021-9258
Statement of
Anuwat Dinudom,Kieran F. Harvey,Permsak Komwatana,Corina N. Jolliffe,John A. Young,Sharad Kumar,and David I. Cook
Abstract: The amiloride-sensitive epithelial Na+ channels (ENaC) in the intralobular duct cells of mouse mandibular glands are inhibited by the ubiquitin-protein ligase, Nedd4, which is activated by increased intracellular Na+. In this study we have used whole-cell patch clamp methods in mouse mandibular duct cells to investigate the role of the C termini of the α-, β-, and γ-subunits of ENaC in mediating this inhibition. We found that peptides corresponding to the C termini of the β- and γ-subunits, but not the α-subunit, inhibited the activity of the Na+ channels. This mechanism did not involve Nedd4 and probably resulted from the exogenous C termini interfering competitively with the protein-protein interactions that keep the channels active. In the case of the C terminus of mouse β-ENaC, the interacting motif included βSer631, βAsp632, and βSer633. In the C terminus of mouse γ-ENaC, it included γSer640. Once these motifs were deleted, we were able to use the C termini of β- and γ-ENaC to prevent Nedd4-mediated down-regulation of Na+ channel activity. The C terminus of the α-subunit, on the contrary, did not prevent Nedd4-mediated inhibition of the Na+ channels. We conclude that mouse Nedd4 interacts with the β- and γ-subunits of ENaC.
Keywords: Mandible
Glutathione Transferase
Sodium Channels
Recombinant Fusion Proteins
DNA, Complementary
Virulence Factors, Bordetella
Patch-Clamp Techniques
Amino Acid Sequence
Amino Acid Motifs
Protein Structure, Tertiary
Sequence Homology, Amino Acid
Dose-Response Relationship, Drug
Molecular Sequence Data
Epithelial Sodium Channels
Rights: © 2001 by The American Society for Biochemistry and Molecular Biology, Inc.
DOI: 10.1074/jbc.M011273200
Published version:
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