The pathway for IRP2 degradation involving 2-oxoglutarate-dependent oxygenase(s) does not require the E3 ubiquitin ligase activity of pVHL

Biochim Biophys Acta. 2005 Mar 22;1743(1-2):79-85. doi: 10.1016/j.bbamcr.2004.08.011.

Abstract

Iron regulatory protein 2 (IRP2), a posttranscriptional regulator of iron metabolism, is subjected to iron-dependent degradation by the proteasome. Recent experiments proposed a mechanism involving 2-oxoglutarate-dependent oxygenases. Enzymes of this class, such as prolyl-4-hydroxylases, mediate the oxygen and iron-dependent degradation of the hypoxia inducible factor HIF-1alpha, which requires the E3 ubiquitin ligase activity of pVHL. Considering that the pathways for IRP2 and HIF-1alpha degradation share remarkable similarities, we investigated whether pVHL may also be involved in the degradation of IRP2. We show here that IRP2 can interact with pVHL in co-transfection/co-immunoprecipitation assays. Furthermore, pVHL is able to promote the ubiquitination and the decay of transfected IRP2. However, the iron-dependent degradation of endogenous IRP2 is not impaired in VHL-deficient cell lines, suggesting that pVHL is not a necessary component of this pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cell Line
  • Cell Line, Tumor
  • Dose-Response Relationship, Drug
  • Green Fluorescent Proteins / metabolism
  • Humans
  • Immunoprecipitation
  • Iron / metabolism
  • Iron Regulatory Protein 2 / metabolism*
  • Ketoglutaric Acids / metabolism*
  • Oxygen / metabolism
  • Oxygenases / metabolism*
  • Plasmids / metabolism
  • Procollagen-Proline Dioxygenase / metabolism
  • Protein Binding
  • Time Factors
  • Transfection
  • Tumor Suppressor Proteins / metabolism*
  • Ubiquitin / metabolism
  • Ubiquitin-Protein Ligases / metabolism*
  • Von Hippel-Lindau Tumor Suppressor Protein

Substances

  • Ketoglutaric Acids
  • Tumor Suppressor Proteins
  • Ubiquitin
  • Green Fluorescent Proteins
  • Iron
  • Oxygenases
  • Procollagen-Proline Dioxygenase
  • Ubiquitin-Protein Ligases
  • Von Hippel-Lindau Tumor Suppressor Protein
  • Iron Regulatory Protein 2
  • VHL protein, human
  • Oxygen