title: DNA damage-induced MDMX degradation is mediated by MDM2.
abstract: Although genetic studies have demonstrated that MDMX is essential to maintain p53 activity at low levels in non-stressed cells, it is unknown whether MDMX regulates p53 activation by DNA damage. We show here that DNA damage-induced p53 induction is associated with rapid down-regulation of the MDMX protein. Significantly, interference with MDMX down-regulation results in the suppression of p53 activation by genotoxic stress. We also demonstrate that DNA damage-induced MDMX reduction is mediated by MDM2, which targets MDMX for proteasomal degradation by a distinct mechanism that permits preferential MDMX degradation and therefore ensures optimal p53 activation.
authors.affiliation: Department of Cancer Cell Biology, Harvard School of Public Health, Boston, Massachusetts 02115, USA.
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Kawai
authors.forename: Dmitri
authors.initials: D
authors.lastname: Wiederschain
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kitao
authors.forename: Jeremy
authors.initials: J
authors.lastname: Stuart
authors.forename: Kelvin K C
authors.initials: KK
authors.lastname: Tsai
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Yuan
mesh_terms: D015153:Blotting, Western; D002453:Cell Cycle; D045744:Cell Line, Tumor; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004249:DNA Damage; D015536:Down-Regulation; D006801:Humans; D008856:Microscopy, Fluorescence; D009097:Multienzyme Complexes / Q000378:metabolism; D009687:Nuclear Proteins; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D046988:Proteasome Endopeptidase Complex; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051736:Proto-Oncogene Proteins c-mdm2; D012190:Retroviridae / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D009097:Multienzyme Complexes; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D016159:Tumor Suppressor Protein p53; D025801:Ubiquitin; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex