The promyelocytic leukemia gene product (PML) forms stable complexes with the retinoblastoma protein

Myriam Alcalay, Lucia Tomassoni, Emanuela Colombo, Stephan Stoldt, Francesco Grignani, Marta Fagioli, Laszlo Szekely, Kristian Helin, Pier Giuseppe Pelicci

Research output: Contribution to journalArticle

Abstract

PML is a nuclear protein with growth-suppressive properties originally identified in the context of the PML-retinoic acid receptor α (RARα) fusion protein of acute promyelocytic leukemia. PML localizes within distinct nuclear structures, called nuclear bodies, which are disrupted by the expression of PML-RARα. We report that PML colocalizes with the nonphosphorylated fraction of the retinoblastoma protein (pRB) within nuclear bodies and that pRB is delocalized by PML-RARα expression. Both PML and PML- RARα form complexes with the nonphosphorylated form of pRB in vivo, and they interact with the pocket region of pRB. The regions of PML and PML-RARα involved in pRB binding differ; in fact, the B boxes and the C-terminal region of PML, the latter of which is not present in PML-RARα, are essential for the formation of stable complexes with pRB. Functionally, PML abolishes activation of glucocorticoid receptor-regulated transcription by pRB, whereas PML-RARα further increases it. Our results suggest that PML may be part of transcription-regulatory complexes and that the oncogenic potential of the PML-RARα protein may derive from the alteration of PML-regulated transcription.

Original languageEnglish
Pages (from-to)1084-1093
Number of pages10
JournalMolecular and Cellular Biology
Volume18
Issue number2
Publication statusPublished - Feb 1998

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ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cell Biology

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