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Nat Struct Mol Biol. 2018 Oct;25(10):971-980. doi: 10.1038/s41594-018-0133-6. Epub 2018 Oct 5.

XLF and APLF bind Ku80 at two remote sites to ensure DNA repair by non-homologous end joining.

Author information

1
Institute for Integrative Biology of the Cell, Institute Joliot, CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France.
2
Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France.
3
Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France.
4
Synchrotron Soleil, L'Orme des Merisiers, Saint-Aubin, Gif-sur-Yvette, France.
5
Signalisations, Noyaux et Innovations en Cancérologie, UMR 8126, CNRS, Université Paris-Sud, Gustave Roussy, Université Paris-Saclay, Villejuif, France.
6
New York University School of Medicine, Perlmutter Cancer Center, New York, USA.
7
Cancer Research Center of Marseille, CNRS UMR 7258, Inserm U1068, Institut Paoli-Calmettes, Aix-Marseille Université UM105, Marseille, France.
8
Dynamic Biosensors GmbH, Martinsried, Germany.
9
BrisSynBio Centre, School of Biochemistry, Faculty of Biomedical Sciences, University of Bristol, Bristol, UK.
10
Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France. calsou@ipbs.fr.
11
Equipe Labellisée Ligue Contre le Cancer 2018, Toulouse, France. calsou@ipbs.fr.
12
Institute for Integrative Biology of the Cell, Institute Joliot, CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France. jb.charbonnier@cea.fr.

Abstract

The Ku70-Ku80 (Ku) heterodimer binds rapidly and tightly to the ends of DNA double-strand breaks and recruits factors of the non-homologous end-joining (NHEJ) repair pathway through molecular interactions that remain unclear. We have determined crystal structures of the Ku-binding motifs (KBM) of the NHEJ proteins APLF (A-KBM) and XLF (X-KBM) bound to a Ku-DNA complex. The two KBM motifs bind remote sites of the Ku80 α/β domain. The X-KBM occupies an internal pocket formed by an unprecedented large outward rotation of the Ku80 α/β domain. We observe independent recruitment of the APLF-interacting protein XRCC4 and of XLF to laser-irradiated sites via binding of A- and X-KBMs, respectively, to Ku80. Finally, we show that mutation of the X-KBM and A-KBM binding sites in Ku80 compromises both the efficiency and accuracy of end joining and cellular radiosensitivity. A- and X-KBMs may represent two initial anchor points to build the intricate interaction network required for NHEJ.

PMID:
30291363
PMCID:
PMC6234012
DOI:
10.1038/s41594-018-0133-6
[Indexed for MEDLINE]
Free PMC Article

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