title: Constitutive association of BRCA1 and c-Abl and its ATM-dependent disruption after irradiation.
abstract: BRCA1 plays an important role in mechanisms of response to double-strand breaks, participating in genome surveillance, DNA repair, and cell cycle checkpoint arrests. Here, we identify a constitutive BRCA1-c-Abl complex and provide evidence for a direct interaction between the PXXP motif in the C terminus of BRCA1 and the SH3 domain of c-Abl. Following exposure to ionizing radiation (IR), the BRCA1-c-Abl complex is disrupted in an ATM-dependent manner, which correlates temporally with ATM-dependent phosphorylation of BRCA1 and ATM-dependent enhancement of the tyrosine kinase activity of c-Abl. The BRCA1-c-Abl interaction is affected by radiation-induced modification to both BRCA1 and c-Abl. We show that the C terminus of BRCA1 is phosphorylated by c-Abl in vitro. In vivo, BRCA1 is phosphorylated at tyrosine residues in an ATM-dependent, radiation-dependent manner. Tyrosine phosphorylation of BRCA1, however, is not required for the disruption of the BRCA1-c-Abl complex. BRCA1-mutated cells exhibit constitutively high c-Abl kinase activity that is not further increased on exposure to IR. We suggest a model in which BRCA1 acts in concert with ATM to regulate c-Abl tyrosine kinase activity.
authors.affiliation: Radiobiologie Cellulaire et Moléculaire, U350 Inserm, Institut Curie, 91405 Orsay, France. nforay@aol.com
authors.forename: Nicolas
authors.initials: N
authors.lastname: Foray
authors.forename: Didier
authors.initials: D
authors.lastname: Marot
authors.forename: Voahangy
authors.initials: V
authors.lastname: Randrianarison
authors.forename: Nicole Dalla
authors.initials: ND
authors.lastname: Venezia
authors.forename: Didier
authors.initials: D
authors.lastname: Picard
authors.forename: Michel
authors.initials: M
authors.lastname: Perricaudet
authors.forename: Vincent
authors.initials: V
authors.lastname: Favaudon
authors.forename: Penny
authors.initials: P
authors.lastname: Jeggo
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins; D019313:BRCA1 Protein / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D001665:Binding Sites; D018797:Cell Cycle Proteins; D002478:Cells, Cultured; D004268:DNA-Binding Proteins; D006801:Humans; D009154:Mutation; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D016315:Proto-Oncogene Proteins c-abl / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D011839:Radiation, Ionizing; D025521:Tumor Suppressor Proteins
chemical_list: D019313:BRCA1 Protein; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D025521:Tumor Suppressor Proteins; D016315:Proto-Oncogene Proteins c-abl; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases