[FXYD proteins: novel regulators of Na,K-ATPase].
Members of the FXYD protein family are small membrane proteins which are characterized by an FXYD motif, two conserved glycines and a serine residue. FXYD proteins show a tissue-specific distribution. Recent evidence suggests that 6 out of 7 FXYD proteins, FXYD1 (phospholemman), FXYD2 (gamma subunit of Na,K-ATPase), FXYD3 (Mat-8), FXYD4 (CHIF), FXYD5 (Ric) and FXYD7 associate with Na,K-ATPase and modulate its transport properties e.g. its Na+ and/or its K+ affinity in a distinct way. These results highlight the complex regulation of Na+ and K+ transport which is necessary to ensure proper tissue functions such as renal Na+-reabsorption, muscle contractility and neuronal excitability. Moreover, mutation of a conserved glycine residue into an arginine residue in FXYD2 has been linked to cases of human hypomagnesemia indicating that dysregulation of Na,K-ATPase by FXYD proteins may be implicated in pathophysiological states. A better characterization of this novel regulatory mechanism of Na,K-ATPase may help to better understand its role in physiological and pathophysiological conditions.
Delprat
Benjamin
B
Département de Pharmacologie et Toxicologie, Université de Lausanne, rue du Bugnon 27, 1005 Lausanne, Suisse.
Bibert
Stéphanie
S
Geering
Käthi
K
D000595:Amino Acid Sequence; D000818:Animals; D001120:Arginine; D001692:Biological Transport; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence; D005998:Glycine; D006706:Homeostasis; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011188:Potassium / Q000378:metabolism; D016415:Sequence Alignment; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000099211:Phospholamban
D001120:Arginine; D002135:Calcium-Binding Proteins; D005998:Glycine; D008565:Membrane Proteins; D011188:Potassium; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D000099211:Phospholamban