Mutation of a cysteine in the first transmembrane segment of Na,K-ATPase alpha subunit confers ouabain resistance
Détails
ID Serval
serval:BIB_258FC6D4782B
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Mutation of a cysteine in the first transmembrane segment of Na,K-ATPase alpha subunit confers ouabain resistance
Périodique
EMBO Journal
ISSN
0261-4189 (Print)
Statut éditorial
Publié
Date de publication
05/1992
Volume
11
Numéro
5
Pages
1681-7
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: May
Research Support, Non-U.S. Gov't --- Old month value: May
Résumé
The cardiac glycoside ouabain inhibits Na,K-ATPase by binding to the alpha subunit. In a highly ouabain resistant clone from the MDCK cell line, we have found two alleles of the alpha subunit in which the cysteine, present in the wild-type first transmembrane segment, is replaced by a tyrosine (Y) or a phenylalanine (F). We have studied the kinetics of ouabain inhibition by measuring the current generated by the Na,K-pump in Xenopus oocytes injected with wild-type and mutated alpha 1 and wild-type beta 1 subunit cRNAs. When these mutations, alpha 1C113Y and alpha 1C113F [according to the published sequence [Verrey et al. (1989) Am. J. Physiol., 256, F1034] were introduced in the alpha 1 subunit of the Na,K-ATPase from Xenopus laevis, the inhibition constant (Ki) of ouabain increased greater than 1000-fold compared with wild-type. A more conservative mutation, serine alpha 1C113S did not change the Ki. We observed that the decreased affinity for ouabain was mainly due to a faster dissociation, but probably also to a slower association. Thus we propose that an amino acid residue of the first transmembrane segment located deep in the plasma membrane participates in the structure and the function of the ouabain binding site.
Mots-clé
Amino Acid Sequence
Animals
Base Sequence
Cell Line
Cloning, Molecular
Cysteine/*genetics
DNA/genetics
Drug Resistance/genetics
Kinetics
Molecular Sequence Data
*Mutation
Na(+)-K(+)-Exchanging ATPase/antagonists & inhibitors/*genetics
Ouabain/metabolism/*pharmacology
Phenylalanine/genetics
Polymerase Chain Reaction
Sequence Alignment
Tyrosine/genetics
Xenopus laevis
Pubmed
Web of science
Création de la notice
24/01/2008 13:37
Dernière modification de la notice
20/08/2019 14:04