title: Cell fate decision mediated by p53 pulses.
abstract: The tumor suppressor p53 plays a crucial role in cellular response to various stresses. Recent experiments have shown that p53 level exhibits a series of pulses after DNA damage caused by ionizing radiation (IR). However, how the p53 pulses govern cell survival and death remains unclear. Here, we develop an integrated model with four modules for the p53 network and explore the mechanism for cell fate decision based on the dynamics of the network. By numerical simulations, the following processes are characterized. First, DNA repair proteins bind to IR-induced double-strand breaks, forming complexes, which are then detected by ataxia telangiectasia mutated (ATM). Activated ATM initiates the p53 oscillator to produce pulses. Consequently, the target genes of p53 are selectively induced to control cell fate. We propose that p53 promotes the repair of minor DNA damage but suppresses the repair of severe damage. We demonstrate that cell fate is determined by the number of p53 pulses relying on the extent of DNA damage. At low damage levels, few p53 pulses evoke cell cycle arrest by inducing p21 and promote cell survival, whereas at high damage levels, sustained p53 pulses trigger apoptosis by inducing p53AIP1. We find that p53 can effectively maintain genomic integrity by regulating the efficiency and fidelity of DNA repair. We also show that stochasticity in the generation and repair of DNA damage leads to variability in cell fate. These findings are consistent with experimental observations and advance our understanding of the dynamics and functions of the p53 network.
authors.affiliation: National Laboratory of Solid State Microstructure and Department of Physics, Nanjing University, Nanjing 210093, China.
authors.forename: Xiao-Peng
authors.initials: XP
authors.lastname: Zhang
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.forename: Zhang
authors.initials: Z
authors.lastname: Cheng
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D000465:Algorithms; D017209:Apoptosis / Q000502:physiology*; D064007:Ataxia Telangiectasia Mutated Proteins; D053148:Caspase 3 / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D002470:Cell Survival; D045304:Cytochromes c / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism; D011839:Radiation, Ionizing; D015398:Signal Transduction / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism / Q000502:physiology*; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D045304:Cytochromes c; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D053148:Caspase 3