PML activates transcription by protecting HIPK2 and p300 from SCF Fbx3-mediated degradation

Yutaka Shima, Takito Shima, Tomoki Chiba, Tatsuro Irimura, Pier Paolo Pandolfi, Issay Kitabayashi

Research output: Contribution to journalArticlepeer-review

73 Citations (Scopus)

Abstract

PML, a nuclear protein, interacts with several transcription factors and their coactivators, such as HIPK2 and p300, resulting in the activation of transcription. Although PML is thought to achieve transcription activation by stabilizing the transcription factor complex, little is known about the underlying molecular mechanism. To clarify the role of PML in transcription regulation, we purified the PML complex and identified Fbxo3 (Fbx3), Skp1, and Cullin1 as novel components of this complex. Fbx3 formed SCFFbx3 ubiquitin ligase and promoted the degradation of HIPK2 and p300 by the ubiquitin-proteasome pathway. PML inhibited this degradation through a mechanism that unexpectedly did not involve inhibition of the ubiquitination of HIPK2. PML, Fbx3, and HIPK2 synergistically activated p53-induced transcription. Our findings suggest that PML stabilizes the transcription factor complex by protecting HIPK2 and p300 from SCFFbx3-induced degradation until transcription is completed. In contrast, the leukemia-associated fusion PML-RARα induced the degradation of HIPK2. We discuss the roles of PML and PML-retinoic acid receptor α, as well as those of HIPK2 and p300 ubiquitination, in transcriptional regulation and leukemogenesis.

Original languageEnglish
Pages (from-to)7126-7138
Number of pages13
JournalMolecular and Cellular Biology
Volume28
Issue number23
DOIs
Publication statusPublished - 12-2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

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