Shieldin complex promotes DNA end-joining and counters homologous recombination in BRCA1-null cells.
de Krijger, I
MetadataShow full item record
BRCA1 deficiencies cause breast, ovarian, prostate and other cancers, and render tumours hypersensitive to poly(ADP-ribose) polymerase (PARP) inhibitors. To understand the resistance mechanisms, we conducted whole-genome CRISPR-Cas9 synthetic-viability/resistance screens in BRCA1-deficient breast cancer cells treated with PARP inhibitors. We identified two previously uncharacterized proteins, C20orf196 and FAM35A, whose inactivation confers strong PARP-inhibitor resistance. Mechanistically, we show that C20orf196 and FAM35A form a complex, 'Shieldin' (SHLD1/2), with FAM35A interacting with single-stranded DNA through its C-terminal oligonucleotide/oligosaccharide-binding fold region. We establish that Shieldin acts as the downstream effector of 53BP1/RIF1/MAD2L2 to promote DNA double-strand break (DSB) end-joining by restricting DSB resection and to counteract homologous recombination by antagonizing BRCA2/RAD51 loading in BRCA1-deficient cells. Notably, Shieldin inactivation further sensitizes BRCA1-deficient cells to cisplatin, suggesting how defining the SHLD1/2 status of BRCA1-deficient tumours might aid patient stratification and yield new treatment opportunities. Highlighting this potential, we document reduced SHLD1/2 expression in human breast cancers displaying intrinsic or acquired PARP-inhibitor resistance.
Cell Line, Tumor
Cell Cycle Proteins
Xenograft Model Antitumor Assays
Dose-Response Relationship, Drug
Drug Resistance, Neoplasm
DNA Breaks, Double-Stranded
DNA End-Joining Repair
Recombinational DNA Repair
Poly(ADP-ribose) Polymerase Inhibitors
Tumor Suppressor p53-Binding Protein 1
Preclinical Modelling of Paediatric Cancer Evolution
License start date
Nature cell biology, 2018, 20 (8), pp. 954 - 965
Showing items related by title, author, creator and subject.
Structural Basis for Auto-Inhibition of the NDR1 Kinase Domain by an Atypically Long Activation Segment. Xiong, S; Lorenzen, K; Couzens, AL; Templeton, CM; Rajendran, D; et al. (2018-08)The human NDR family kinases control diverse aspects of cell growth, and are regulated through phosphorylation and association with scaffolds such as MOB1. Here, we report the crystal structure of the human NDR1 kinase ...
Phosphorylation-mediated interactions with TOPBP1 couple 53BP1 and 9-1-1 to control the G1 DNA damage checkpoint. Bigot, N; Day, M; Baldock, RA; Watts, FZ; Oliver, AW; et al. (2019-05-28)Coordination of the cellular response to DNA damage is organised by multi-domain 'scaffold' proteins, including 53BP1 and TOPBP1, which recognise post-translational modifications such as phosphorylation, methylation and ...
Broderick, R; Nieminuszczy, J; Blackford, AN; Winczura, A; Niedzwiedz, W (2015-03-12)During mitosis, sister chromatids must be faithfully segregated to ensure that daughter cells receive one copy of each chromosome. However, following replication they often remain entangled. Topoisomerase IIα (TOP2A) has ...