title: FXYD proteins: new tissue- and isoform-specific regulators of Na,K-ATPase.
abstract: The recently defined FXYD protein family contains seven members that are small, single-span membrane proteins characterized by a signature sequence containing an FXYD motif and three other conserved amino acid residues. Until recently, the functional role of FXYD proteins was largely unknown, with the exception of the gamma subunit of Na,K-ATPase, which was shown to be a specific regulator of renal alpha1-beta1 isozymes. We have investigated whether other members of the FXYD family may have a similar role as the gamma subunit and have found that CHIF (corticosteroid hormone-induced factor, FXYD4), FXYD7, as well as phospholemman (FXYD1) specifically associate with Na,K-ATPase and preferentially with alpha1-beta isozymes in native tissues, and produce distinct effects on the transport properties of Na,K-ATPase that are adapted to the physiological demands of the tissues in which they are expressed. These results provide evidence for a unique and novel mode of regulation of Na,K-ATPase by FXYD proteins that involves a tissue-specific expression of an auxiliary subunit of distinct Na,K-ATPase isozymes.
authors.affiliation: Institute of Pharmacology and Toxicology, University of Lausanne, Switzerland. kaethi.geering@ipharm.unil.ch
authors.forename: Käthi
authors.initials: K
authors.lastname: Geering
authors.forename: Pascal
authors.initials: P
authors.lastname: Béguin
authors.forename: Haim
authors.initials: H
authors.lastname: Garty
authors.forename: Steven
authors.initials: S
authors.lastname: Karlish
authors.forename: Maria
authors.initials: M
authors.lastname: Füzesi
authors.forename: Jean-Daniel
authors.initials: JD
authors.lastname: Horisberger
authors.forename: Gilles
authors.initials: G
authors.lastname: Crambert
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003106:Colon; D017124:Conserved Sequence; D007413:Intestinal Mucosa / Q000201:enzymology; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D007668:Kidney / Q000201:enzymology*; D008247:Lysosomes / Q000201:enzymology; D008565:Membrane Proteins / Q000378:metabolism*; D009474:Neurons / Q000201:enzymology; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D008565:Membrane Proteins; D021122:Protein Subunits; D000254:Sodium-Potassium-Exchanging ATPase