title: The prolyl isomerase Pin1 affects Che-1 stability in response to apoptotic DNA damage.
abstract: We have previously demonstrated that DNA damage leads to stabilization and accumulation of Che-1, an RNA polymerase II-binding protein that plays an important role in transcriptional activation of p53 and in maintenance of the G(2)/M checkpoint. Here we show that Che-1 is down-regulated during the apoptotic process. We found that the E3 ligase HMD2 physically and functionally interacts with Che-1 and promotes its degradation via the ubiquitin-dependent proteasomal system. Furthermore, we found that in response to apoptotic stimuli Che-1 interacts with the peptidyl-prolyl isomerase Pin1 and that conformational changes generated by Pin1 are required for Che-1/HDM2 interaction. Notably, a Che-1 mutant lacking the capacity to bind Pin1 exhibits an increased half-life and this correlates with a diminished apoptosis in response to genotoxic stress. Our results establish Che-1 as a new Pin1 and HDM2 target and confirm its important role in the cellular response to DNA damage.
authors.affiliation: Laboratory B, Experimental Research Center and Rome Oncogenomic Center, Regina Elena Cancer Institute, Via delle Messi d'Oro 156, 00158 Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: De Nicola
authors.forename: Tiziana
authors.initials: T
authors.lastname: Bruno
authors.forename: Simona
authors.initials: S
authors.lastname: Iezzi
authors.forename: Monica
authors.initials: M
authors.lastname: Di Padova
authors.forename: Aristide
authors.initials: A
authors.lastname: Floridi
authors.forename: Claudio
authors.initials: C
authors.lastname: Passananti
authors.forename: Giannino
authors.initials: G
authors.lastname: Del Sal
authors.forename: Maurizio
authors.initials: M
authors.lastname: Fanciulli
mesh_terms: D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D045744:Cell Line, Tumor; D004249:DNA Damage; D015536:Down-Regulation; D016195:G2 Phase; D006801:Humans; D051379:Mice; D009154:Mutation; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D019696:Peptidylprolyl Isomerase / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism
chemical_list: C402637:AATF protein, human; D051017:Apoptosis Regulatory Proteins; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D012097:Repressor Proteins; D014157:Transcription Factors; D025801:Ubiquitin; C497206:MDM2 protein, human; C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2; D044767:Ubiquitin-Protein Ligases; D046988:Proteasome Endopeptidase Complex; C000606846:PIN1 protein, human; D019696:Peptidylprolyl Isomerase; C000606850:Pin1 protein, mouse