Abstract
The promyelocytic leukaemia (PML) tumour-suppressor protein potentiates p53 function by regulating post-translational modifications, such as CBP-dependent acetylation and Chk2-dependent phosphorylation, in the PML-Nuclear Body (NB). PML was recently shown to interact with the p53 ubiquitin-ligase Mdm2 (refs 4-6); however, the mechanism by which PML regulates Mdm2 remains unclear. Here, we show that PML enhances p53 stability by sequestering Mdm2 to the nucleolus. We found that after DNA damage, PML and Mdm2 accumulate in the nucleolus in an Arf-independent manner. In addition, we found that the nucleolar localization of PML is dependent on ATR activation and phosphorylation of PML by ATR. Notably, in Pml(-/-) cells, sequestration of Mdm2 to the nucleolus was impaired, as well as p53 stabilization and the induction of apoptosis. Furthermore, we demonstrate that PML physically associates with the nucleolar protein L11, and that L11 knockdown impairs the ability of PML to localize to nucleoli after DNA damage. These findings demonstrate an unexpected role of PML in the nucleolar network for tumour suppression.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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ADP-Ribosylation Factor 1 / genetics
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ADP-Ribosylation Factor 1 / metabolism
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Active Transport, Cell Nucleus / genetics
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Animals
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Ataxia Telangiectasia Mutated Proteins
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Cell Compartmentation / genetics
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Cell Line, Transformed
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Cell Nucleolus / genetics
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Cell Nucleolus / metabolism*
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Cells, Cultured
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Fibroblasts
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Humans
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Mice
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NIH 3T3 Cells
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Neoplasm Proteins / genetics
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Neoplasm Proteins / metabolism*
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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Phosphorylation
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Promyelocytic Leukemia Protein
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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Protein Transport / genetics
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism*
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Proto-Oncogene Proteins c-mdm2
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RNA Stability / genetics
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Ribosomal Proteins / genetics
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Ribosomal Proteins / metabolism
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Tumor Suppressor Protein p53 / genetics
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Tumor Suppressor Protein p53 / metabolism*
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Tumor Suppressor Proteins / genetics
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Tumor Suppressor Proteins / metabolism*
Substances
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Cell Cycle Proteins
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Neoplasm Proteins
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Nuclear Proteins
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Pml protein, mouse
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Promyelocytic Leukemia Protein
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Proto-Oncogene Proteins
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Ribosomal Proteins
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Transcription Factors
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Tumor Suppressor Protein p53
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Tumor Suppressor Proteins
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ribosomal protein L11
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PML protein, human
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MDM2 protein, human
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Mdm2 protein, mouse
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Proto-Oncogene Proteins c-mdm2
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Atr protein, mouse
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ATR protein, human
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Ataxia Telangiectasia Mutated Proteins
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Protein Serine-Threonine Kinases
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ADP-Ribosylation Factor 1