title: BRCA1 Directs the Repair Pathway to Homologous Recombination by Promoting 53BP1 Dephosphorylation.
abstract: BRCA1 promotes homologous recombination (HR) by activating DNA-end resection. By contrast, 53BP1 forms a barrier that inhibits DNA-end resection. Here, we show that BRCA1 promotes DNA-end resection by relieving the 53BP1-dependent barrier. We show that 53BP1 is phosphorylated by ATM in S/G2phase, promoting RIF1 recruitment, which inhibits resection. 53BP1 is promptly dephosphorylated and RIF1 released, despite remaining unrepaired DNA double-strand breaks (DSBs). When resection is impaired by CtIP/MRE11 endonuclease inhibition, 53BP1 phosphorylation and RIF1 are sustained due to ongoing ATM signaling. BRCA1 depletion also sustains 53BP1 phosphorylation and RIF1 recruitment. We identify the phosphatase PP4C as having a major role in 53BP1 dephosphorylation and RIF1 release. BRCA1 or PP4C depletion impairs 53BP1 repositioning, EXO1 recruitment, and HR progression. 53BP1 or RIF1 depletion restores resection, RAD51 loading, and HR in PP4C-depleted cells. Our findings suggest that BRCA1 promotes PP4C-dependent 53BP1 dephosphorylation and RIF1 release, directing repair toward HR.
authors.affiliation: Advanced Scientific Research Leaders Development Unit, Gunma University, Maebashi, Gunma 371-8511, Japan; Gunma University Heavy Ion Medical Center, Gunma University, Maebashi, Gunma 371-8511, Japan.
authors.forename: Mayu
authors.initials: M
authors.lastname: Isono
authors.affiliation: Gunma University Initiative for Advanced Research, Gunma University, Maebashi, Gunma 371-8511, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Niimi
authors.affiliation: Department of Radiation Oncology, Gunma University, Maebashi, Gunma 371-8511, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Oike
authors.affiliation: Advanced Scientific Research Leaders Development Unit, Gunma University, Maebashi, Gunma 371-8511, Japan; Department of Radiation Oncology, Gunma University, Maebashi, Gunma 371-8511, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Hagiwara
authors.affiliation: Department of Radiation Oncology, Gunma University, Maebashi, Gunma 371-8511, Japan.
authors.forename: Hiro
authors.initials: H
authors.lastname: Sato
authors.affiliation: Advanced Scientific Research Leaders Development Unit, Gunma University, Maebashi, Gunma 371-8511, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Sekine
authors.affiliation: Gunma University Heavy Ion Medical Center, Gunma University, Maebashi, Gunma 371-8511, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Yoshida
authors.affiliation: Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan.
authors.forename: Shin-Ya
authors.initials: SY
authors.lastname: Isobe
authors.affiliation: Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan.
authors.forename: Chikashi
authors.initials: C
authors.lastname: Obuse
authors.affiliation: Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Nishi
authors.affiliation: Department of Biotechnology, Chemistry, and Pharmacy, Università degli Studi di Siena, 53100 Siena, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Petricci
authors.affiliation: Department of Bioregulation and Cellular Response, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Nakada
authors.affiliation: Gunma University Heavy Ion Medical Center, Gunma University, Maebashi, Gunma 371-8511, Japan; Gunma University Initiative for Advanced Research, Gunma University, Maebashi, Gunma 371-8511, Japan; Department of Radiation Oncology, Gunma University, Maebashi, Gunma 371-8511, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakano
authors.affiliation: Advanced Scientific Research Leaders Development Unit, Gunma University, Maebashi, Gunma 371-8511, Japan. Electronic address: shibata.at@gunma-u.ac.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shibata
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism; D019313:BRCA1 Protein / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000378:metabolism; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases / Q000378:metabolism; D016195:G2 Phase; D059765:Homologous Recombination; D006801:Humans; D000076228:MRE11 Homologue Protein / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D016196:S Phase; D015398:Signal Transduction; D034501:Telomere-Binding Proteins / Q000378:metabolism; D000071857:Tumor Suppressor p53-Binding Protein 1 / Q000378:metabolism*
chemical_list: D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D002352:Carrier Proteins; C121766:MRE11 protein, human; D009687:Nuclear Proteins; C492743:Rif1 protein, human; C498301:TP53BP1 protein, human; D034501:Telomere-Binding Proteins; D000071857:Tumor Suppressor p53-Binding Protein 1; D064007:Ataxia Telangiectasia Mutated Proteins; C114331:EXO1 protein, human; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; D000076228:MRE11 Homologue Protein; C410741:RBBP8 protein, human; D010749:Phosphoprotein Phosphatases; C080406:protein phosphatase 4; D045643:DNA Repair Enzymes
keywords: 53BP1; ATM; BRCA1; DNA-end resection; HR; NHEJ; PP4C; RIF1