Mutational analysis of cysteine-rich domains of the epithelium sodium channel (ENaC). Identification of cysteines essential for channel expression at the cell surface.

Détails

ID Serval
serval:BIB_2414C5C9EC90
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Mutational analysis of cysteine-rich domains of the epithelium sodium channel (ENaC). Identification of cysteines essential for channel expression at the cell surface.
Périodique
Journal of Biological Chemistry
Auteur(s)
Firsov D., Robert-Nicoud M., Gruender S., Schild L., Rossier B.C.
ISSN
0021-9258 (Print)
ISSN-L
0021-9258
Statut éditorial
Publié
Date de publication
1999
Volume
274
Numéro
5
Pages
2743-2749
Langue
anglais
Résumé
One of the characteristic features of the structure of the epithelial sodium channel family (ENaC) is the presence of two highly conserved cysteine-rich domains (CRD1 and CRD2) in the large extracellular loops of the proteins. We have studied the role of CRDs in the functional expression of rat alphabetagamma ENaC subunits by systematically mutating cysteine residues (singly or in combinations) into either serine or alanine. In the Xenopus oocyte expression system, mutations of two cysteines in CRD1 of alpha, beta, or gamma ENaC subunits led to a temperature-dependent inactivation of the channel. In CRD1, one of the cysteines of the rat alphaENaC subunit (Cys158) is homologous to Cys133 of the corresponding human subunit causing, when mutated to tyrosine (C133Y), pseudohypoaldosteronism type 1, a severe salt-loosing syndrome in neonates. In CRD2, mutation of two cysteines in alpha and beta but not in the gamma subunit also produced a temperature-dependent inactivation of the channel. The main features of the mutant cysteine channels are: (i) a decrease in cell surface expression of channel molecules that parallels the decrease in channel activity and (ii) a normal assembly or rate of degradation as assessed by nondenaturing co-immunoprecipitation of [35S]methionine-labeled channel protein. These data indicate that the two cysteines in CRD1 and CRD2 are not a prerequisite for subunit assembly and/or intrinsic channel activity. We propose that they play an essential role in the efficient transport of assembled channels to the plasma membrane.
Mots-clé
Animals, Cysteine/genetics, DNA Mutational Analysis, Epithelial Sodium Channel, Humans, Mutagenesis, Site-Directed, Protein Conformation, Rats, Serine/genetics, Sodium Channels/genetics, Surface Properties, Xenopus
Pubmed
Web of science
Création de la notice
24/01/2008 13:32
Dernière modification de la notice
20/08/2019 14:02
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