Reconstitution of Mdm2-Dependent Post-Translational Modifications of p53 in Yeast

• Published in: PloS one Vol. 3; no. 1; p. e1507
• Main Authors: Di Ventura, Barbara, Funaya, Charlotta, Antony, Claude, Knop, Michael, Serrano, Luis
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30.01.2008; Public Library of Science (PLoS)
• Subjects: Apoptosis; Biodegradation; Cell Biology/Cell Signaling; Cell cycle; Cell Nucleus - metabolism; Cloning; Computational Biology/Signaling Networks; Computational Biology/Synthetic Biology; Deoxyribonucleic acid; DNA; DNA damage; Enzymes; Eukaryotes; Fungal Proteins - metabolism; Gene expression; Humans; Kinases; Laboratories; Leukemia; Localization; Lysine; Malfunctions; MDM2 protein; Microscopy; Microscopy, Electron; Molecular biology; Molecular Biology/Nucleolus and Nuclear Bodies; Molecular Biology/Post-Translational Regulation of Gene Expression; Mutagenesis; Mutation; Oncology; p53 Protein; Plasmids; Post-translation; Protein interaction; Protein Processing, Post-Translational; Protein Transport; Proteins; Recruitment; Regulations; Saccharomyces cerevisiae; Saccharomyces cerevisiae - metabolism; SUMO protein; SUMO-1 Protein - metabolism; Translation; Tumor proteins; Tumor Suppressor Protein p14ARF - metabolism; Tumor Suppressor Protein p53 - metabolism; Yeast; Germany
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0001507

p53 mediates cell cycle arrest or apoptosis in response to DNA damage. Its activity is subject to a tight regulation involving a multitude of post-translational modifications. The plethora of functional protein interactions of p53 at present precludes a clear understanding of regulatory principles in the p53 signaling network. To circumvent this complexity, we studied here the minimal requirements for functionally relevant p53 post-translational modifications by expressing human p53 together with its best characterized modifier Mdm2 in budding yeast. We find that expression of the human p53-Mdm2 module in yeast is sufficient to faithfully recapitulate key aspects of p53 regulation in higher eukaryotes, such as Mdm2-dependent targeting of p53 for degradation, sumoylation at lysine 386 and further regulation of this process by p14(ARF). Interestingly, sumoylation is necessary for the recruitment of p53-Mdm2 complexes to yeast nuclear bodies morphologically akin to human PML bodies. These results suggest a novel role for Mdm2 as well as for p53 sumoylation in the recruitment of p53 to nuclear bodies. The reductionist yeast model that was established and validated in this study will now allow to incrementally study simplified parts of the intricate p53 network, thus helping elucidate the core mechanisms of p53 regulation as well as test novel strategies to counteract p53 malfunctions.