1. Autologous K63 deubiquitylation within the BRCA1-A complex licenses DNA damage recognition.
- Author
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Jiang Q, Foglizzo M, Morozov YI, Yang X, Datta A, Tian L, Thada V, Li W, Zeqiraj E, and Greenberg RA
- Subjects
- Animals, Chromatography, Liquid, DNA Repair, HeLa Cells, Humans, Mice, Tandem Mass Spectrometry, Ubiquitin metabolism, BRCA1 Protein genetics, BRCA1 Protein metabolism, DNA Damage, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Deubiquitinating Enzymes genetics, Deubiquitinating Enzymes metabolism, Histone Chaperones genetics, Histone Chaperones metabolism
- Abstract
The BRCA1-A complex contains matching lysine-63 ubiquitin (K63-Ub) binding and deubiquitylating activities. How these functionalities are coordinated to effectively respond to DNA damage remains unknown. We generated Brcc36 deubiquitylating enzyme (DUB) inactive mice to address this gap in knowledge in a physiologic system. DUB inactivation impaired BRCA1-A complex damage localization and repair activities while causing early lethality when combined with Brca2 mutation. Damage response dysfunction in DUB-inactive cells corresponded to increased K63-Ub on RAP80 and BRCC36. Chemical cross-linking coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and cryogenic-electron microscopy (cryo-EM) analyses of isolated BRCA1-A complexes demonstrated the RAP80 ubiquitin interaction motifs are occupied by ubiquitin exclusively in the DUB-inactive complex, linking auto-inhibition by internal K63-Ub chains to loss of damage site ubiquitin recognition. These findings identify RAP80 and BRCC36 as autologous DUB substrates in the BRCA1-A complex, thus explaining the evolution of matching ubiquitin-binding and hydrolysis activities within a single macromolecular assembly., (© 2022 Jiang et al.)
- Published
- 2022
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