Cobalt inhibits the interaction between hypoxia-inducible factor-alpha and von Hippel-Lindau protein by direct binding to hypoxia-inducible factor-alpha

J Biol Chem. 2003 May 2;278(18):15911-6. doi: 10.1074/jbc.M300463200. Epub 2003 Feb 26.

Abstract

The hypoxia-inducible factor (HIF) activates the expression of genes that contain a hypoxia response element. The alpha-subunits of the HIF transcription factors are degraded by proteasomal pathways during normoxia but are stabilized under hypoxic conditions. The von Hippel-Lindau protein (pVHL) mediates the ubiquitination and rapid degradation of HIF-alpha (including HIF-1alpha and HIF-2alpha). Post-translational hydroxylation of a proline residue in the oxygen-dependent degradation (ODD) domain of HIF-alpha is required for the interaction between HIF and VHL. It has previously been established that cobalt mimics hypoxia and causes accumulation of HIF-1alpha and HIF-2alpha. However, little is known about the mechanism by which this occurs. In an earlier study, we demonstrated that cobalt binds directly to the ODD domain of HIF-2alpha. Here we provide the first evidence that cobalt inhibits pVHL binding to HIF-alpha even when HIF-alpha is hydroxylated. Deletion of 17 amino acids within the ODD domain of HIF-2alpha that are required for pVHL binding prevented the binding of cobalt and stabilized HIF-2alpha during normoxia. These findings show that cobalt mimics hypoxia, at least in part, by occupying the VHL-binding domain of HIF-alpha and thereby preventing the degradation of HIF-alpha.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Basic Helix-Loop-Helix Transcription Factors
  • CHO Cells
  • Cobalt / pharmacology*
  • Cricetinae
  • Deferoxamine / pharmacology
  • Glycine / analogs & derivatives*
  • Hydroxylation
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Ligases / metabolism*
  • Molecular Sequence Data
  • Rats
  • Trans-Activators / chemistry
  • Trans-Activators / metabolism*
  • Transcription Factors / metabolism*
  • Tumor Suppressor Proteins*
  • Ubiquitin-Protein Ligases*
  • Von Hippel-Lindau Tumor Suppressor Protein

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Trans-Activators
  • Transcription Factors
  • Tumor Suppressor Proteins
  • PC 12 ester
  • endothelial PAS domain-containing protein 1
  • Cobalt
  • Ubiquitin-Protein Ligases
  • Von Hippel-Lindau Tumor Suppressor Protein
  • Ligases
  • Deferoxamine
  • Glycine