The breast cancer tumor suppressor BRCA2 promotes the specific targeting of RAD51 to single-stranded DNA

Thorslund, Tina; McIlwraith, Michael J.; Compton, Sarah A.; Lekomtsev, Sergey; Petronczki, Mark; Griffith, Jack D.; West, Stephen C.

doi:10.1038/nsmb.1905

Cited by 233 publications

(227 citation statements)

References 22 publications

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“…However, Srs2 contains a BRC repeat variant (BRCv, a.a.836–860). Srs2‐BRCv structurally resembles the BRC repeat of the human tumour suppressor BRCA2 (Islam et al , 2012) which mediates BRCA2–RAD51 interaction, thereby promoting recruitment of RAD51 to DSBs and regulation of RAD51 recombinase activity (Jensen et al , 2010; Liu et al , 2010; Thorslund et al , 2010). Srs2‐BRCv also promotes Srs2–Rad51 interaction in vitro (Islam et al , 2012).…”

Section: Discussionmentioning

confidence: 99%

Unloading of homologous recombination factors is required for restoring double‐stranded DNA at damage repair loci

et al. 2017

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Cells use homology‐dependent DNA repair to mend chromosome breaks and restore broken replication forks, thereby ensuring genome stability and cell survival. DNA break repair via homology‐based mechanisms involves nuclease‐dependent DNA end resection, which generates long tracts of single‐stranded DNA required for checkpoint activation and loading of homologous recombination proteins Rad52/51/55/57. While recruitment of the homologous recombination machinery is well characterized, it is not known how its presence at repair loci is coordinated with downstream re‐synthesis of resected DNA. We show that Rad51 inhibits recruitment of proliferating cell nuclear antigen (PCNA), the platform for assembly of the DNA replication machinery, and that unloading of Rad51 by Srs2 helicase is required for efficient PCNA loading and restoration of resected DNA. As a result, srs2Δ mutants are deficient in DNA repair correlating with extensive DNA processing, but this defect in srs2Δ mutants can be suppressed by inactivation of the resection nuclease Exo1. We propose a model in which during re‐synthesis of resected DNA, the replication machinery must catch up with the preceding processing nucleases, in order to close the single‐stranded gap and terminate further resection.

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Section: Discussionmentioning

confidence: 99%

Unloading of homologous recombination factors is required for restoring double‐stranded DNA at damage repair loci

et al. 2017

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“…However, only filaments formed on the ssDNA substrates are productive in homologous pairing and DNA strand exchange (41). The recombination mediator BRCA2 is known to promote a bias in binding affinity favoring the ssDNA (36,37,42). We investigated the effect of RAD51 phosphorylation on the RAD51-dsDNA and RAD51-ssDNA interactions by incubating the RAD51 phosphomimetic mutants with linearized ϕX174 dsDNA or ϕX174 ssDNA and analyzing the electrophoretic mobility-shift assay (EMSA).…”

Section: Rad51 Phosphomimetic Mutants Efficiently Overcome the Kineticmentioning

confidence: 99%

Tyrosine phosphorylation stimulates activity of human RAD51 recombinase through altered nucleoprotein filament dynamics

Subramanyam

Ismail

Bhattacharya

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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The DNA strand exchange protein RAD51 facilitates the central step in homologous recombination, a process fundamentally important for accurate repair of damaged chromosomes, restart of collapsed replication forks, and telomere maintenance. The active form of RAD51 is a nucleoprotein filament that assembles on single-stranded DNA (ssDNA) at the sites of DNA damage. The c-Abl tyrosine kinase and its oncogenic counterpart BCR-ABL fusion kinase phosphorylate human RAD51 on tyrosine residues 54 and 315. We combined biochemical reconstitutions of the DNA strand exchange reactions with total internal reflection fluorescence microscopy to determine how the two phosphorylation events affect the biochemical activities of human RAD51 and properties of the RAD51 nucleoprotein filament. By mimicking RAD51 tyrosine phosphorylation with a nonnatural amino acid, p-carboxymethyl-L-phenylalanine (pCMF), we demonstrated that Y54 phosphorylation enhances the RAD51 recombinase activity by at least two different mechanisms, modifies the RAD51 nucleoprotein filament formation, and allows RAD51 to compete efficiently with ssDNA binding protein RPA. In contrast, Y315 phosphorylation has little effect on the RAD51 activities. Based on our work and previous cellular studies, we propose a mechanism underlying RAD51 activation by c-Abl/BCR-ABL kinases.RAD51 recombinase | c-Abl tyrosine kinase | homologous recombination | single-molecule total internal reflection fluorescence microscopy | phosphorylation T he DNA in the human genome is constantly subjected to damage. This damage is a byproduct of normal cellular metabolism, exposure to radiation, and environmental mutagens (1). Homologous recombination (HR) and the pathways that use the machinery of HR are responsible for the accurate repair of the most deleterious DNA lesions, including double-stranded DNA breaks (DSBs), interstrand DNA cross-links, and damaged replication forks, and thereby contribute to maintenance of the stable genome (2-5). HR also plays an important role in telomere maintenance (6). HR, a process highly conserved throughout evolution, is carried out through a precisely coordinated and tightly regulated series of events. The key step in HR is the assembly of a RecA-family recombinase (phage UvsX, bacterial RecA, archaeal RadA, or eukaryotic RAD51) onto resected single-stranded DNA (ssDNA). The recombinase forms a nucleoprotein filament that then invades homologous duplex DNA, resulting in a displacement loop structure that can be used as a primer for synthesis using the intact duplex as a template. Similar to its bacterial and yeast homologs, the human RAD51 binds ssDNA in an ATP-dependent manner (7). The nucleoprotein filament formed by the ATP-bound RAD51 is arranged such that each RAD51 monomer binds three nucleotides, forming the pairing unit in these reactions (8). Beyond these basic attributes, the characteristics of human RAD51 protein differ significantly from its archaeal, bacterial, and yeast homologs.The critical role of HR requires all steps of this process ...

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“…Human BRCA2 and its orthologs are an important positive regulatory element for HR (5)(6)(7). BRCA2 directly interacts with RAD51 recombinase and recruits it to double strand breaks.…”

Section: Homologous Recombination (Hr)mentioning

confidence: 99%

A Variant of the Breast Cancer Type 2 Susceptibility Protein (BRC) Repeat Is Essential for the RECQL5 Helicase to Interact with RAD51 Recombinase for Genome Stabilization

Islam

Paquet

Fox

et al. 2012

Journal of Biological Chemistry

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Background:The BRC repeat is essential for BRCA2 to bind RAD51 and promote homologous recombination. Results: A BRC repeat variant is essential for RECQL5 to bind RAD51 and suppress homologous recombination. Conclusion: The BRC repeat can be utilized to either promote or suppress homologous recombination. Significance: Discovery of multiple functions of the BRC repeat is important for understanding regulation of homologous recombination.

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The breast cancer tumor suppressor BRCA2 promotes the specific targeting of RAD51 to single-stranded DNA

Cited by 233 publications

References 22 publications

Unloading of homologous recombination factors is required for restoring double‐stranded DNA at damage repair loci

Unloading of homologous recombination factors is required for restoring double‐stranded DNA at damage repair loci

Tyrosine phosphorylation stimulates activity of human RAD51 recombinase through altered nucleoprotein filament dynamics

A Variant of the Breast Cancer Type 2 Susceptibility Protein (BRC) Repeat Is Essential for the RECQL5 Helicase to Interact with RAD51 Recombinase for Genome Stabilization

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