Arsenic degrades PML or PML-RARalpha through a SUMO-triggered RNF4/ubiquitin-mediated pathway

Nat Cell Biol. 2008 May;10(5):547-55. doi: 10.1038/ncb1717. Epub 2008 Apr 13.


In acute promyelocytic leukaemia (APL), arsenic trioxide induces degradation of the fusion protein encoded by the PML-RARA oncogene, differentiation of leukaemic cells and produces clinical remissions. SUMOylation of its PML moiety was previously implicated, but the nature of the degradation pathway involved and the role of PML-RARalpha catabolism in the response to therapy have both remained elusive. Here, we demonstrate that arsenic-induced PML SUMOylation triggers its Lys 48-linked polyubiquitination and proteasome-dependent degradation. When exposed to arsenic, SUMOylated PML recruits RNF4, the human orthologue of the yeast SUMO-dependent E3 ubiquitin-ligase, as well as ubiquitin and proteasomes onto PML nuclear bodies. Arsenic-induced differentiation is impaired in cells transformed by a non-degradable PML-RARalpha SUMOylation mutant or in APL cells transduced with a dominant-negative RNF4, directly implicating PML-RARalpha catabolism in the therapeutic response. We thus identify PML as the first protein degraded by SUMO-dependent polyubiquitination. As PML SUMOylation recruits not only RNF4, ubiquitin and proteasomes, but also many SUMOylated proteins onto PML nuclear bodies, these domains could physically integrate the SUMOylation, ubiquitination and degradation pathways.

Publication types

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

MeSH terms

  • Animals
  • Arsenic / metabolism*
  • Cell Differentiation / physiology
  • Cell Line
  • Humans
  • Mice
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Oncogene Proteins, Fusion / genetics
  • Oncogene Proteins, Fusion / metabolism*
  • Polyubiquitin / metabolism
  • Promyelocytic Leukemia Protein
  • Proteasome Endopeptidase Complex / metabolism
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • SUMO-1 Protein / genetics
  • SUMO-1 Protein / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism*


  • Neoplasm Proteins
  • Nuclear Proteins
  • Oncogene Proteins, Fusion
  • Promyelocytic Leukemia Protein
  • RNA, Small Interfering
  • RNF4 protein, human
  • Recombinant Fusion Proteins
  • SUMO-1 Protein
  • Transcription Factors
  • Tumor Suppressor Proteins
  • promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein
  • Polyubiquitin
  • PML protein, human
  • Proteasome Endopeptidase Complex
  • Arsenic