title: Delayed activation of Bax by DNA damage in embryonic stem cells with knock-in mutations of the Abl nuclear localization signals.
abstract: The non-receptor tyrosine kinase Abl contains nuclear localization (NLS) and nuclear export signals that drive its nucleo-cytoplasmic shuttling. The nuclear Abl tyrosine kinase is activated by DNA damage through ataxia telangiectasia mutated (ATM). Previous studies have suggested nuclear Abl to have proapoptotic activity. To determine the requirement for Abl nuclear import in DNA damage-induced apoptosis, we took a genetic approach by mutating the three NLS (muNLS) of abl1 in mouse embryonic stem (ES) cells through homologous recombination. Exposure of ES cells to genotoxins caused an ATM-dependent nuclear accumulation of Abl but not Abl muNLS. ES cells expressing Abl muNLS exhibited delayed Bax activation, reduced cytochrome c release and decreased caspase-9 activity in response to DNA damage. These results provide a genetic proof that Abl nuclear entry contributes to DNA damage-induced activation of the intrinsic apoptotic pathway.
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, and Moores-UCSD Cancer Center, University of California, San Diego School of Medicine, La Jolla, CA 92093-0820, USA.
authors.forename: M
authors.initials: M
authors.lastname: Preyer
authors.forename: C-W
authors.initials: CW
authors.lastname: Shu
authors.forename: J Y J
authors.initials: JY
authors.lastname: Wang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D064007:Ataxia Telangiectasia Mutated Proteins; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D002945:Cisplatin / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D047468:Immunoprecipitation; D051379:Mice; D009154:Mutation; D019913:Nuclear Localization Signals / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D016315:Proto-Oncogene Proteins c-abl / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects / Q000528:radiation effects; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism; D014466:Ultraviolet Rays; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D019913:Nuclear Localization Signals; D025521:Tumor Suppressor Proteins; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c; D016315:Proto-Oncogene Proteins c-abl; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D017346:Protein Serine-Threonine Kinases; D053148:Caspase 3; D053453:Caspase 9; D002945:Cisplatin