Structural and functional features of the transmembrane domain of the Na,K-ATPase beta subunit revealed by tryptophan scanning.

Détails

ID Serval
serval:BIB_45A3A05A7CB6
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Structural and functional features of the transmembrane domain of the Na,K-ATPase beta subunit revealed by tryptophan scanning.
Périodique
Journal of Biological Chemistry
Auteur(s)
Hasler U., Crambert G., Horisberger J.D., Geering K.
ISSN
0021-9258
Statut éditorial
Publié
Date de publication
05/2001
Peer-reviewed
Oui
Volume
276
Numéro
19
Pages
16356-16364
Langue
anglais
Résumé
In oligomeric P2-ATPases such as Na,K- and H,K-ATPases, beta subunits play a fundamental role in the structural and functional maturation of the catalytic alpha subunit. In the present study we performed a tryptophan scanning analysis on the transmembrane alpha-helix of the Na,K-ATPase beta1 subunit to investigate its role in the stabilization of the alpha subunit, the endoplasmic reticulum exit of alpha-beta complexes, and the acquisition of functional properties of the Na,K-ATPase. Single or multiple tryptophan substitutions in the beta subunits transmembrane domain had no significant effect on the structural maturation of alpha subunits expressed in Xenopus oocytes nor on the level of expression of functional Na,K pumps at the cell surface. Furthermore, tryptophan substitutions in regions of the transmembrane alpha-helix containing two GXXXG transmembrane helix interaction motifs or a cysteine residue, which can be cross-linked to transmembrane helix M8 of the alpha subunit, had no effect on the apparent K(+) affinity of Na,K-ATPase. On the other hand, substitutions by tryptophan, serine, alanine, or cysteine, but not by phenylalanine of two highly conserved tyrosine residues, Tyr(40) and Tyr(44), on another face of the transmembrane helix, perturb the transport kinetics of Na,K pumps in an additive way. These results indicate that at least two faces of the beta subunits transmembrane helix contribute to inter- or intrasubunit interactions and that two tyrosine residues aligned in the beta subunits transmembrane alpha-helix are determinants of intrinsic transport characteristics of Na,K-ATPase.
Mots-clé
Amino Acid Sequence, Amino Acid Substitution, Animals, Cell Membrane/enzymology, Endoplasmic Reticulum/enzymology, Glycine, Kinetics, Membrane Potentials, Models, Molecular, Molecular Sequence Data, Mutagenesis, Site-Directed, Protein Structure, Secondary, Protein Subunits, Recombinant Proteins/chemistry, Recombinant Proteins/metabolism, Sodium-Potassium-Exchanging ATPase/chemistry, Sodium-Potassium-Exchanging ATPase/metabolism, Tryptophan, Xenopus
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2008 13:28
Dernière modification de la notice
08/05/2019 17:54
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