Structural and functional properties of two human FXYD3 (Mat-8) isoforms.

Détails

ID Serval
serval:BIB_C225883B10A8
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Structural and functional properties of two human FXYD3 (Mat-8) isoforms.
Périodique
Journal of Biological Chemistry
Auteur(s)
Bibert S., Roy S., Schaer D., Felley-Bosco E., Geering K.
ISSN
0021-9258 (Print)
ISSN-L
0021-9258
Statut éditorial
Publié
Date de publication
2006
Peer-reviewed
Oui
Volume
281
Numéro
51
Pages
39142-39151
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Résumé
Six of 7 FXYD proteins have been shown to be tissue-specific modulators of Na,K-ATPase. In this study, we have identified two splice variants of human FXYD3, or Mat-8, in CaCo-2 cells. Short human FXYD3 has 72% sequence identity with mouse FXYD3, whereas long human FXYD3 is identical to short human FXYD3 but has a 26-amino acid insertion after the transmembrane domain. Short and long human FXYD3 RNAs and proteins are differentially expressed during differentiation of CaCo-2 cells. Long human FXYD3 is mainly expressed in nondifferentiated cells and short human FXYD3 in differentiated cells and both FXYD3 variants can be co-immunoprecipitated with a Na,K-ATPase antibody. In contrast to mouse FXYD3, which has two transmembrane domains for lack of cleavage of the signal peptide, human FXYD3 has a cleavable signal peptide and adopts a type I topology. After co-expression in Xenopus oocytes, both human FXYD3 variants associate stably only with Na,K-ATPase isozymes but not with H,K-ATPase or Ca-ATPase. Similar to mouse FXYD3, short human FXYD3 decreases the apparent K(+) and Na(+) affinity of Na,K-ATPase over a large range of membrane potentials. On the other hand, long human FXYD3 decreases the apparent K(+) affinity only at slightly negative and positive membrane potentials and increases the apparent Na(+) affinity of Na,K-ATPase. Finally, both short and long human FXYD3 induce a hyperpolarization activated current, similar to that induced by mouse FXYD3. Thus, we have characterized two human FXYD3 isoforms that are differentially expressed in differentiated and non-differentiated cells and show different functional properties.
Mots-clé
Animals, Caco-2 Cells, Cell Differentiation, Cell Membrane/metabolism, Gene Expression Regulation, Gene Expression Regulation, Enzymologic, Gene Expression Regulation, Neoplastic, Humans, Membrane Proteins/chemistry, Membrane Proteins/physiology, Mice, Neoplasm Proteins/chemistry, Neoplasm Proteins/physiology, Potassium/chemistry, Protein Conformation, Protein Isoforms, Sodium-Potassium-Exchanging ATPase/metabolism, Xenopus
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2008 13:28
Dernière modification de la notice
20/08/2019 16:37
Données d'usage