Membrane topology of the epithelial sodium channel in intact cells

Détails

ID Serval
serval:BIB_87804C711A1C
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Membrane topology of the epithelial sodium channel in intact cells
Périodique
American Journal of Physiology
Auteur(s)
Canessa  C. M., Merillat  A. M., Rossier  B. C.
ISSN
0363-6143
Statut éditorial
Publié
Date de publication
12/1994
Volume
267
Numéro
6 Pt 1
Pages
C1682-90
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Dec
Résumé
The highly selective amiloride-sensitive epithelial sodium channel is formed of three homologous subunits termed alpha-, beta-, and gamma-rENaC. Each subunit has two putative transmembrane domains (M1 and M2), yielding a protein with a large (approximately 50 kDa) hydrophilic loop (between M1 and M2) and short hydrophilic NH2- and COOH-termini (9 and 10 kDa). All three subunits are glycosylated in a cell-free translation assay, demonstrating that they share in vitro a common pattern of membrane insertion. The membrane topology of the alpha-rENaC subunit in intact cells was studied in Xenopus laevis oocytes. We demonstrate that 1) all six potential N-linked glycosylation sites (N190, N259, N320, N339, N424, and N538) of the large hydrophilic loop are used in intact cells; 2) the glycosylation of alpha-rENaC does not play a significant role in the functional expression of the channel; and 3) the two hydrophobic domains M1 (A109-F131) and M2 (S588-L612) serve in intact cells as start- and stop-transfer signals, respectively. We conclude that alpha-rENaC spans the membrane twice with the short NH2- and COOH-terminal ends on the cytoplasmic side and a large hydrophilic loop in the extracellular space.
Mots-clé
Amiloride/pharmacology Animals Cell Membrane/*chemistry Cytoskeleton/physiology Dogs Glycosylation Mutagenesis, Site-Directed Rabbits Sodium Channels/*chemistry/physiology Structure-Activity Relationship Xenopus laevis
Pubmed
Création de la notice
24/01/2008 14:01
Dernière modification de la notice
03/03/2018 19:02
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