Role of the transmembrane domain of FXYD7 in structural and functional interactions with Na,K-ATPase.

Details

Serval ID
serval:BIB_125F08251A71
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Role of the transmembrane domain of FXYD7 in structural and functional interactions with Na,K-ATPase.
Journal
Journal of Biological Chemistry
Author(s)
Li C., Crambert G., Thuillard D., Roy S., Schaer D., Geering K.
ISSN
0021-9258
Publication state
Published
Issued date
12/2005
Peer-reviewed
Oui
Volume
280
Number
52
Pages
42738-42743
Language
english
Notes
Publication types: Journal Article
Abstract
Members of the FXYD family are tissue-specific regulators of the Na,K-ATPase. Here, we have investigated the contribution of amino acids in the transmembrane (TM) domain of FXYD7 to the interaction with Na,K-ATPase. Twenty amino acids of the TM domain were replaced individually by tryptophan, and combined mutations and alanine insertion mutants were constructed. Wild type and mutant FXYD7 were expressed in Xenopus oocytes with Na,K-ATPase. Mutational effects on the stable association with Na,K-ATPase and on the functional regulation of Na,K-ATPase were determined by co-immunoprecipitation and two-electrode voltage clamp techniques, respectively. Most residues important for the structural and functional interaction of FXYD7 are clustered in a face of the TM helix containing the two conserved glycine residues, but others are scattered over two-thirds of the FXYD TM helix. Ile-35, Ile-43, and Ile-44 are only involved in the stable association with Na,K-ATPase. Glu-26, Met-30, and Ile-44 are important for the functional effect and/or the efficient association of FXYD7 with Na,K-ATPase, consistent with the prediction that these amino acids contact TM domain 9 of the alpha subunit (Li, C., Grosdidier, A., Crambert, G., Horisberger, J.-D., Michielin, O., and Geering, K. (2004) J. Biol. Chem. 279, 38895-38902). Several amino acids that are not implicated in the efficient association of FXYD7 with the Na,K-ATPase are specifically involved in the functional effect of FXYD7. Leu-32 and Phe-37 influence the apparent affinity for external K+, whereas Val-28 and Ile-42 are implicated in the apparent affinity for both external K+ and external Na+. These amino acids act in a synergistic way. These results highlight the important structural and functional role of the TM domain of FXYD7 and delineate the determinants that mediate the complex interactions of FXYD7 with Na,K-ATPase.
Keywords
Adenosine Triphosphatases/chemistry, Alanine/chemistry, Amino Acids/chemistry, Animals, Cell Membrane/metabolism, Cloning, Molecular, Dimerization, Electrophysiology, Glycine/chemistry, Immunoprecipitation, Isoleucine/chemistry, Membrane Glycoproteins/chemistry, Membrane Glycoproteins/physiology, Membrane Potentials, Mice, Mutagenesis, Site-Directed, Mutation, Nerve Tissue Proteins/chemistry, Nerve Tissue Proteins/physiology, Oocytes/metabolism, Patch-Clamp Techniques, Polymerase Chain Reaction, Potassium/chemistry, Protein Binding, Protein Structure, Tertiary, RNA, Complementary/metabolism, Rats, Sodium-Potassium-Exchanging ATPase/chemistry, Sodium-Potassium-Exchanging ATPase/metabolism, Structure-Activity Relationship, Tryptophan/chemistry, Valine/chemistry, Xenopus
Pubmed
Web of science
Open Access
Yes
Create date
24/01/2008 12:28
Last modification date
20/08/2019 12:40
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