This Article Full Text Full Text (PDF) Supplemental material Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Google Scholar Articles by Wu, P.-Y. Articles by Junop, M. S. PubMed PubMed Citation Articles by Wu, P.-Y. Articles by Junop, M. S.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, June 2009, p. 3163-3172, Vol. 29, No. 11
0270-7306/09/$08.00+0     doi:10.1128/MCB.01895-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Structural and Functional Interaction between the Human DNA Repair Proteins DNA Ligase IV and XRCC4 ^,

Peï-Yu Wu,^1,2 Philippe Frit,^1,2* SriLakshmi Meesala,³ Stéphanie Dauvillier,^1,2 Mauro Modesti,⁴ Sara N. Andres,³ Ying Huang,⁵ JoAnn Sekiguchi,⁵ Patrick Calsou,^1,2 Bernard Salles,^1,2 and Murray S. Junop^3,6*

CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), 205 Route de Narbonne, F-31077 Toulouse, France,¹ Université de Toulouse, UPS, IPBS, F-31077 Toulouse, France,² Department of Biochemistry and Biomedical Sciences, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada,³ CNRS, Unité Propre de Recherche 3081, Genome Instability and Carcinogenesis Conventionné par l'Université d'Aix-Marseille 2, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France,⁴ Departments of Internal Medicine and Human Genetics, University of Michigan Ann Arbor, Michigan 48109,⁵ Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada⁶

Received 14 December 2008/ Returned for modification 27 January 2009/ Accepted 24 March 2009

Nonhomologous end-joining represents the major pathway used by human cells to repair DNA double-strand breaks. It relies on the XRCC4/DNA ligase IV complex to reseal DNA strands. Here we report the high-resolution crystal structure of human XRCC4 bound to the carboxy-terminal tandem BRCT repeat of DNA ligase IV. The structure differs from the homologous Saccharomyces cerevisiae complex and reveals an extensive DNA ligase IV binding interface formed by a helix-loop-helix structure within the inter-BRCT linker region, as well as significant interactions involving the second BRCT domain, which induces a kink in the tail region of XRCC4. We further demonstrate that interaction with the second BRCT domain of DNA ligase IV is necessary for stable binding to XRCC4 in cells, as well as to achieve efficient dominant-negative effects resulting in radiosensitization after ectopic overexpression of DNA ligase IV fragments in human fibroblasts. Together our findings provide unanticipated insight for understanding the physical and functional architecture of the nonhomologous end-joining ligation complex.

---

* Corresponding author. Mailing address for Philippe Frit: IPBS, 205 Route de Narbonne, F-31077 Toulouse cedex, France. Phone: (33) 561-17-59-37. Fax: (33) 561-17-59-33. E-mail: philippe.frit{at}ipbs.fr. Mailing address for Murray S. Junop: Department of Biochemistry and Biomedical Sciences, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada. Phone: (905) 525-9140. Fax: (905) 522-9033. E-mail: junopm{at}mcmaster.ca

Published ahead of print on 30 March 2009.

Supplemental material for this article may be found at http://mcb.asm.org/.

---

Molecular and Cellular Biology, June 2009, p. 3163-3172, Vol. 29, No. 11
0270-7306/09/$08.00+0     doi:10.1128/MCB.01895-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Killen, M. W., Stults, D. M., Adachi, N., Hanakahi, L., Pierce, A. J. (2009). Loss of Bloom syndrome protein destabilizes human gene cluster architecture. Hum Mol Genet 18: 3417-3428 [Abstract] [Full Text]