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

J Zhu, M Gianni, E Kopf, N Honoré… - Proceedings of the …, 1999 - National Acad Sciences
J Zhu, M Gianni, E Kopf, N Honoré, M Chelbi-Alix, M Koken, F Quignon, C Rochette-Egly…
Proceedings of the National Academy of Sciences, 1999National Acad Sciences
Analyzing the pathways by which retinoic acid (RA) induces promyelocytic leukemia/retinoic
acid receptor α (PML/RAR α) catabolism in acute promyelocytic leukemia (APL), we found
that, in addition to caspase-mediated PML/RAR α cleavage, RA triggers degradation of both
PML/RAR α and RAR α. Similarly, in non-APL cells, RA directly targeted RAR α and RAR α
fusions to the proteasome degradation pathway. Activation of either RAR α or RXR α by
specific agonists induced degradation of both proteins. Conversely, a mutation in RAR α that …
Analyzing the pathways by which retinoic acid (RA) induces promyelocytic leukemia/retinoic acid receptor α (PML/RARα) catabolism in acute promyelocytic leukemia (APL), we found that, in addition to caspase-mediated PML/RARα cleavage, RA triggers degradation of both PML/RARα and RARα. Similarly, in non-APL cells, RA directly targeted RARα and RARα fusions to the proteasome degradation pathway. Activation of either RARα or RXRα by specific agonists induced degradation of both proteins. Conversely, a mutation in RARα that abolishes heterodimer formation and DNA binding, blocked both RARα and RXRα degradation. Mutations in the RARα DNA-binding domain or AF-2 transcriptional activation region also impaired RARα 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.
National Acad Sciences