p18(Hamlet) mediates different p53-dependent responses to DNA-damage inducing agents.
Cells organize appropriate responses to environmental cues by activating specific signaling networks. Two proteins that play key roles in coordinating stress responses are the kinase p38alpha (MAPK14) and the transcription factor p53 (TP53). Depending on the nature and the extent of the stress-induced damage, cells may respond by arresting the cell cycle or by undergoing cell death, and these responses are usually associated with the phosphorylation of particular substrates by p38alpha as well as the activation of specific target genes by p53. We recently characterized a new p38alpha substrate, named p18(Hamlet) (ZNHIT1), which mediates p53-dependent responses to different genotoxic stresses. Thus, cisplatin or UV light induce stabilization of the p18(Hamlet) protein, which then enhances the ability of p53 to bind to and activate the promoters of pro-apoptotic genes such as NOXA and PUMA leading to apoptosis induction. In a similar way, we report here that p18(Hamlet) can also mediate the cell cycle arrest induced in response to gamma-irradiation, by participating in the p53-dependent upregulation of the cell cycle inhibitor p21(Cip1) (CDKN1A).
Lafarga
Vanesa
V
CNIO (Spanish National Cancer Center), Madrid, Spain.
Cuadrado
Ana
A
Nebreda
Angel R
AR
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects / Q000528:radiation effects*; D002460:Cell Line; D002843:Chromatin; D002945:Cisplatin / Q000494:pharmacology; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects; D005720:Gamma Rays; D005786:Gene Expression Regulation; D006801:Humans; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D051017:Apoptosis Regulatory Proteins; C438378:BBC3 protein, human; D002843:Chromatin; D050759:Cyclin-Dependent Kinase Inhibitor p21; C498702:PMAIP1 protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D015534:Trans-Activators; D016159:Tumor Suppressor Protein p53; C523208:p18(Hamlet) protein, human; D002945:Cisplatin