Hypoxia-mediated Na-K-ATPase degradation requires von Hippel Lindau protein

FASEB J. 2008 May;22(5):1335-42. doi: 10.1096/fj.07-8369com. Epub 2007 Dec 11.

Abstract

Hypoxia inhibits Na-K-ATPase activity and leads to its degradation in mammalian cells. Von Hippel Lindau protein (pVHL) and hypoxia inducible factor (HIF) are key mediators in cellular adaptation to hypoxia; thus, we set out to investigate whether pVHL and HIF participate in the hypoxia-mediated degradation of plasma membrane Na-K-ATPase. We found that in the presence of pVHL hypoxia decreased Na-K-ATPase activity and promoted the degradation of plasma membrane Na-K-ATPase. In pVHL-deficient cells, hypoxia did not decrease the Na-K-ATPase activity and the degradation of plasma membrane Na-K-ATPase was prevented. pVHL-mediated degradation of Na-K-ATPase required the functional pVHL E3 ligase and Ubc5 since pVHL mutants and dominant-negative Ubc5 prevented Na-K-ATPase from degradation. The generation of reactive oxygen species was necessary for pVHL-mediated Na-K-ATPase degradation during hypoxia. Desferrioxamine, which stabilizes HIF1/2alpha, did not affect the half-life of plasma membrane Na-K-ATPase. In addition, stabilizing HIF1/2alpha by infecting mammalian cells with adenoviruses containing the oxygen-dependent degradation domain of HIF1alpha did not affect the plasma membrane Na-K-ATPase degradation. In cells with suppression of pVHL by short hairpin RNA, the Na-K-ATPase was not degraded during hypoxia, whereas cells with knockdown of HIF1/2alpha retained the ability to degrade plasma membrane Na-K-ATPase. These findings suggest that pVHL participates in the hypoxia-mediated degradation of plasma membrane Na-K-ATPase in a HIF-independent manner.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / physiology
  • COS Cells
  • Cell Membrane / enzymology
  • Cells, Cultured
  • Chlorocebus aethiops
  • Deferoxamine / pharmacology
  • Humans
  • Hypoxia / metabolism*
  • Hypoxia-Inducible Factor 1, alpha Subunit / physiology
  • Organometallic Compounds / pharmacology
  • Salicylates / pharmacology
  • Sodium-Potassium-Exchanging ATPase / metabolism*
  • Von Hippel-Lindau Tumor Suppressor Protein / physiology*

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • EUK-134
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Organometallic Compounds
  • Salicylates
  • endothelial PAS domain-containing protein 1
  • Von Hippel-Lindau Tumor Suppressor Protein
  • Sodium-Potassium-Exchanging ATPase
  • Deferoxamine