Human BRCA1-BARD1 ubiquitin ligase activity counteracts chromatin barriers to DNA resection

Ruth M Densham; Alexander J Garvin; Helen R Stone; Joanna Strachan; Robert A Baldock; Manuel Daza-Martin; Alice Fletcher; Sarah Blair-Reid; James Beesley; Balraj Johal; Laurence H Pearl; Robert Neely; Nicholas H Keep; Felicity Z Watts; Joanna R Morris

doi:10.1038/nsmb.3236

Human BRCA1-BARD1 ubiquitin ligase activity counteracts chromatin barriers to DNA resection

Nat Struct Mol Biol. 2016 Jul;23(7):647-55. doi: 10.1038/nsmb.3236. Epub 2016 May 30.

Authors

Affiliations

¹ Birmingham Centre for Genome Biology, Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
² Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK.
³ School of Chemistry, University of Birmingham, Birmingham, UK.
⁴ Department of Biological Sciences, Institute for Structural and Molecular Biology, Birkbeck, University of London, London, UK.

Abstract

The opposing activities of 53BP1 and BRCA1 influence pathway choice in DNA double-strand-break repair. How BRCA1 counteracts the inhibitory effect of 53BP1 on DNA resection and homologous recombination is unknown. Here we identify the site of BRCA1-BARD1 required for priming ubiquitin transfer from E2∼ubiquitin and demonstrate that BRCA1-BARD1's ubiquitin ligase activity is required for repositioning 53BP1 on damaged chromatin. We confirm H2A ubiquitination by BRCA1-BARD1 and show that an H2A-ubiquitin fusion protein promotes DNA resection and repair in BARD1-deficient cells. BRCA1-BARD1's function in homologous recombination requires the chromatin remodeler SMARCAD1. SMARCAD1 binding to H2A-ubiquitin and optimal localization to sites of damage and activity in DNA repair requires its ubiquitin-binding CUE domains. SMARCAD1 is required for 53BP1 repositioning, and the need for SMARCAD1 in olaparib or camptothecin resistance is alleviated by 53BP1 loss. Thus, BRCA1-BARD1 ligase activity and subsequent SMARCAD1-dependent chromatin remodeling are critical regulators of DNA repair.

MeSH terms

BRCA1 Protein / genetics*
BRCA1 Protein / metabolism
Binding Sites
Camptothecin / pharmacology
Chromatin / chemistry
Chromatin / drug effects
Chromatin / metabolism*
Cloning, Molecular
DNA Breaks, Double-Stranded
DNA Cleavage / drug effects
DNA Helicases / genetics*
DNA Helicases / metabolism
DNA, Neoplasm / genetics*
DNA, Neoplasm / metabolism
Escherichia coli / genetics
Escherichia coli / metabolism
Gene Expression
Gene Expression Regulation, Neoplastic*
HeLa Cells
Histones / genetics
Histones / metabolism
Humans
Models, Molecular
Phthalazines / pharmacology
Piperazines / pharmacology
Protein Binding
Recombinant Proteins / genetics
Recombinant Proteins / metabolism
Recombinational DNA Repair*
Signal Transduction
Tumor Suppressor Proteins / genetics*
Tumor Suppressor Proteins / metabolism
Tumor Suppressor p53-Binding Protein 1 / genetics
Tumor Suppressor p53-Binding Protein 1 / metabolism
Ubiquitin / genetics
Ubiquitin / metabolism
Ubiquitin-Protein Ligases / genetics*
Ubiquitin-Protein Ligases / metabolism
Ubiquitination / drug effects

Substances

BRCA1 Protein
BRCA1 protein, human
Chromatin
DNA, Neoplasm
Histones
Phthalazines
Piperazines
Recombinant Proteins
TP53BP1 protein, human
Tumor Suppressor Proteins
Tumor Suppressor p53-Binding Protein 1
Ubiquitin
BARD1 protein, human
Ubiquitin-Protein Ligases
SMARCAD1 protein, human
DNA Helicases
olaparib
Camptothecin

Abstract

MeSH terms

Substances

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