Hydrophobic C-terminal amino acids in the beta-subunit are involved in assembly with the alpha-subunit of Na,K-ATPase

Détails

ID Serval
serval:BIB_E4D35135811B
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Hydrophobic C-terminal amino acids in the beta-subunit are involved in assembly with the alpha-subunit of Na,K-ATPase
Périodique
Biochemistry
Auteur⸱e⸱s
Beggah  A. T., Beguin  P., Jaunin  P., Peitsch  M. C., Geering  K.
ISSN
0006-2960 (Print)
Statut éditorial
Publié
Date de publication
12/1993
Volume
32
Numéro
51
Pages
14117-24
Notes
Comparative Study
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Dec 28
Résumé
To define the structural basis of oligomerization for the alpha- and beta-subunits of Na,K-ATPase, we have attempted to identify the amino acids in the C-terminus of the beta-subunit that are involved in subunit assembly. We predicted that the last 10 amino acids form a beta-strand-like structure exposing on one side a hydrophilic and on the other side a continuous hydrophobic domain. The relative importance of the two domains in assembly was probed by introducing point mutations in either domain of Xenopus beta 3-subunits and by testing the ability of these mutants to stabilize newly synthesized alpha-subunits expressed in Xenopus oocytes and to form functional alpha-beta complexes at the plasma membrane. All single and double mutants with changes at R268 and/or K272 to either uncharged or negatively charged amino acids associated with coexpressed alpha-subunits and increased the number of ouabain binding sites and Rb uptake into oocytes. On the other hand, mutations affecting the hydrophobic amino acids influenced the assembly efficiency with alpha-subunits to a variable extent. The single mutants V269N and I275N did not influence and the mutant V273N slightly affected the assembly process. On the other hand, the cellular accumulation of alpha-subunits and the expression of functional Na,K pumps was considerably reduced with the mutant F271N and totally abolished with the double mutant V269N/F271N. Finally, replacement of V269 and F271 or V273 and I275 with the less hydrophobic alanine also significantly decreased subunit assembly, which was no longer detectable after replacement of all four amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)
Mots-clé
Amino Acid Sequence Animals Humans Macromolecular Substances Microinjections Molecular Sequence Data Mutagenesis, Site-Directed Na(+)-K(+)-Exchanging ATPase/*chemistry Oocytes/enzymology Ouabain/metabolism Protein Structure, Secondary Rabbits Rats Sequence Alignment Sequence Homology, Amino Acid Structure-Activity Relationship Xenopus laevis
Pubmed
Web of science
Création de la notice
24/01/2008 12:28
Dernière modification de la notice
20/08/2019 16:08
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