title: Activating transcription factor 3, a stress sensor, activates p53 by blocking its ubiquitination.
abstract: Activating transcription factor 3 (ATF3) is rapidly induced by diverse environmental insults including genotoxic stress. We report herein that its interaction with p53, enhanced by genotoxic stress, stabilizes the tumor suppressor thereby augmenting functions of the latter. Overexpression of ATF3 (but not a mutated ATF3 protein (Delta102-139) devoid of its p53-binding region) prevents p53 from MDM2-mediated degradation and leads to increased transcription from p53-regulated promoters. ATF3, but not the Delta102-139 protein, binds the p53 carboxy-terminus and diminishes its ubiquitination and nuclear export. Genotoxic-stressed ATF3-null mouse embryonic fibroblasts, or cells in which ATF3 was reduced by small interference RNA, show inefficient p53 induction and impaired apoptosis compared with wild-type cells. ATF3-null cells (but not wild-type cells), which poorly accumulate p53, are transformed by oncogenic Ras. Thus, ATF3 is a novel stress-activated regulator of p53 protein stability/function providing the cell with a means of responding to a wide range of environmental insult, thus maintaining DNA integrity and protecting against cell transformation.
authors.affiliation: Department of Cancer Biology, MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Chunhong
authors.initials: C
authors.lastname: Yan
authors.forename: Dan
authors.initials: D
authors.lastname: Lu
authors.forename: Tsonwin
authors.initials: T
authors.lastname: Hai
authors.forename: Douglas D
authors.initials: DD
authors.lastname: Boyd
mesh_terms: D051700:Activating Transcription Factor 3; D021581:Active Transport, Cell Nucleus; D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002471:Cell Transformation, Neoplastic; D004249:DNA Damage; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D011905:Genes, ras; D006801:Humans; D051379:Mice; D009153:Mutagens / Q000633:toxicity*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C490449:ATF3 protein, human; D051700:Activating Transcription Factor 3; D009153:Mutagens; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D016159:Tumor Suppressor Protein p53; C497206:MDM2 protein, human; C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2; D044767:Ubiquitin-Protein Ligases