Retinoic acid induces proteasome-dependent degradation of retinoic acid receptor alpha (RARalpha) and oncogenic RARalpha fusion proteins

Proc Natl Acad Sci U S A. 1999 Dec 21;96(26):14807-12. doi: 10.1073/pnas.96.26.14807.

Abstract

Analyzing the pathways by which retinoic acid (RA) induces promyelocytic leukemia/retinoic acid receptor alpha (PML/RARalpha) catabolism in acute promyelocytic leukemia (APL), we found that, in addition to caspase-mediated PML/RARalpha cleavage, RA triggers degradation of both PML/RARalpha and RARalpha. Similarly, in non-APL cells, RA directly targeted RARalpha and RARalpha fusions to the proteasome degradation pathway. Activation of either RARalpha or RXRalpha by specific agonists induced degradation of both proteins. Conversely, a mutation in RARalpha that abolishes heterodimer formation and DNA binding, blocked both RARalpha and RXRalpha degradation. Mutations in the RARalpha DNA-binding domain or AF-2 transcriptional activation region also impaired RARalpha catabolism. Hence, our results link transcriptional activation to receptor catabolism and suggest that transcriptional up-regulation of nuclear receptors by their ligands may be a feedback mechanism allowing sustained target-gene activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caspases / metabolism
  • Cysteine Endopeptidases / metabolism*
  • DNA Mutational Analysis
  • Dimerization
  • Leukemia, Promyelocytic, Acute / metabolism
  • Multienzyme Complexes / metabolism*
  • Neoplasm Proteins / metabolism*
  • Oncogene Proteins, Fusion / metabolism*
  • Proteasome Endopeptidase Complex
  • Receptors, Retinoic Acid / genetics
  • Receptors, Retinoic Acid / metabolism*
  • Retinoic Acid Receptor alpha
  • Retinoid X Receptors
  • Transcription Factors / metabolism
  • Tretinoin / pharmacology*

Substances

  • Multienzyme Complexes
  • Neoplasm Proteins
  • Oncogene Proteins, Fusion
  • Receptors, Retinoic Acid
  • Retinoic Acid Receptor alpha
  • Retinoid X Receptors
  • Transcription Factors
  • promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein
  • Tretinoin
  • Caspases
  • Cysteine Endopeptidases
  • Proteasome Endopeptidase Complex