title: DNA damage-induced nuclear translocation of Apaf-1 is mediated by nucleoporin Nup107.
abstract: Beside its central role in the mitochondria-dependent cell death pathway, the apoptotic protease activating factor 1 (Apaf-1) is involved in the DNA damage response through cell-cycle arrest induced by genotoxic stress. This non-apoptotic function requires a nuclear translocation of Apaf-1 during the G1-to-S transition. However, the mechanisms that trigger the nuclear accumulation of Apaf-1 upon DNA damage remain to be investigated. Here we show that the main 4 isoforms of Apaf-1 can undergo nuclear translocation and restore Apaf-1 deficient MEFs cell cycle arrest in the S phase following genotoxic stress through activation of Chk-1. Interestingly, DNA damage-dependent nuclear accumulation of Apaf-1 occurs independently of p53 and the retinoblastoma (pRb) pathway. We demonstrated that Apaf-1 associates with the nucleoporin Nup107 and this association is necessary for Apaf-1 nuclear import. The CED-4 domain of Apaf-1 directly binds to the central domain of Nup107 in an ATR-regulated, phosphorylation-dependent manner. Interestingly, expression of the Apaf-1-interacting domain of Nup107 interfered with Apaf-1 nuclear translocation upon genotoxic stress, resulting in a marked reduction of Chk-1 activation and cell cycle arrest. Thus, our results confirm the crucial role of Apaf-1 nuclear relocalization in mediating cell-cycle arrest induced by genotoxic stress and implicate Nup107 as a critical regulator of the DNA damage-induced intra-S phase checkpoint response.
authors.affiliation: a INSERM UMRS1160; Université Denis Diderot; Institut Universitaire d'Hématologie ; Hôpital Saint-Louis ; Paris , France.
authors.forename: Léonard
authors.initials: L
authors.lastname: Jagot-Lacoussiere
authors.forename: Audrey
authors.initials: A
authors.lastname: Faye
authors.forename: Heriberto
authors.initials: H
authors.lastname: Bruzzoni-Giovanelli
authors.forename: Bruno O
authors.initials: BO
authors.lastname: Villoutreix
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Rain
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Poyet
mesh_terms: D000818:Animals; D053477:Apoptotic Protease-Activating Factor 1 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D064007:Ataxia Telangiectasia Mutated Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D000071877:Checkpoint Kinase 1; D002945:Cisplatin / Q000633:toxicity; D004249:DNA Damage / Q000187:drug effects; D006801:Humans; D051379:Mice; D028861:Nuclear Pore Complex Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000378:metabolism; D059807:S Phase Cell Cycle Checkpoints / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism
chemical_list: D053477:Apoptotic Protease-Activating Factor 1; C512772:NUP107 protein, human; D028861:Nuclear Pore Complex Proteins; D020033:Protein Isoforms; D034741:RNA, Small Interfering; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D011494:Protein Kinases; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D000071877:Checkpoint Kinase 1; D002945:Cisplatin
keywords: Apaf-1; Apaf-1, apoptotic protease activating factor 1; Apoptosome; CARD, caspase activation recruitment domain; DAPI, 4′-diamino-2-phenylindole; DNA damage; GST, glutathione S-transferase; MEFs, Mouse Embryonic Fibroblasts; NSCLC, non-small cell lung cancer; Nup107; PI, propidium iodide; cell cycle; cisplatin; nuclear pore complex; nucleoporin