TRIM25 has a dual function in the p53/Mdm2 circuit.
P53 is an important tumor suppressor that, upon activation, induces growth arrest and cell death. Control of p53 is thus of prime importance for proliferating cells, but also for cancer therapy, where p53 activity contributes to the eradication of tumors. Mdm2 functionally inhibits p53 and targets the tumor suppressor protein for degradation. In a genetic screen, we identified TRIM25 as a novel regulator of p53 and Mdm2. TRIM25 increased p53 and Mdm2 abundance by inhibiting their ubiquitination and degradation in 26 S proteasomes. TRIM25 co-precipitated with p53 and Mdm2 and interfered with the association of p300 and Mdm2, a critical step for p53 polyubiquitination. Despite the increase in p53 levels, p53 activity was inhibited in the presence of TRIM25. Downregulation of TRIM25 resulted in an increased acetylation of p53 and p53-dependent cell death in HCT116 cells. Upon genotoxic insults, TRIM25 dampened the p53-dependent DNA damage response. The downregulation of TRIM25 furthermore resulted in massive apoptosis during early embryogenesis of medaka, which was rescued by the concomitant downregulation of p53, demonstrating the functional relevance of the regulation of p53 by TRIM25 in an organismal context.
Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany.|Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany.
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P
Zhang
Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany.
S
S
Elabd
Institute of Pathology, Faculty of Medicine, University of Halle-Wittenberg, Halle, Germany.
S
S
Hammer
Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany.
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V
Solozobova
Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany.|Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany.
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H
Yan
Institute of Pathology, Faculty of Medicine, University of Halle-Wittenberg, Halle, Germany.
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F
Bartel
Department of Anti-Aging Medicine, University of Tokyo, Tokyo, Japan.
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S
Inoue
Chemistry/Biology Combined Major Program, International College, Osaka University, Osaka, Japan.
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T
Henrich
Center for Organismal Studies, Developmental Biology and Physiology, Heidelberg University, Heidelberg, Germany.
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http://orcid.org/0000-0001-8550-7377
J
Wittbrodt
Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany.
F
F
Loosli
Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany.
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G
Davidson
Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany.
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C
Blattner
D000818:Animals; D017209:Apoptosis; D045744:Cell Line, Tumor; D004249:DNA Damage; D045325:HCT116 Cells; D006801:Humans; D061986:MCF-7 Cells; D009990:Oryzias / Q000196:embryology* / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D000070584:Tripartite Motif Proteins; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D054875:Ubiquitination
C495901:TP53 protein, human; D014157:Transcription Factors; D000070584:Tripartite Motif Proteins; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; C084523:TRIM25 protein, human; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease