Visualization of a DNA-PK/PARP1 complex

Spagnolo, L. , Barbeau, J., Curtin, N. J., Morris, E. P. and Pearl, L. H. (2012) Visualization of a DNA-PK/PARP1 complex. Nucleic Acids Research, 40(9), pp. 4168-4177. (doi: 10.1093/nar/gkr1231) (PMID:22223246) (PMCID:PMC3351162)

Abstract

The DNA-dependent protein kinase (DNA-PK) and Poly(ADP-ribose) polymerase-1 (PARP1) are critical enzymes that reduce genomic damage caused by DNA lesions. They are both activated by DNA strand breaks generated by physiological and environmental factors, and they have been shown to interact. Here, we report in vivo evidence that DNA-PK and PARP1 are equally necessary for rapid repair. We purified a DNA-PK/PARP1 complex loaded on DNA and performed electron microscopy and single particle analysis on its tetrameric and dimer-of-tetramers forms. By comparison with the DNA-PK holoenzyme and fitting crystallographic structures, we see that the PARP1 density is in close contact with the Ku subunit. Crucially, PARP1 binding elicits substantial conformational changes in the DNA-PK synaptic dimer assembly. Taken together, our data support a functional, in-pathway role for DNA-PK and PARP1 in double-strand break (DSB) repair. We also propose a NHEJ model where protein–protein interactions alter substantially the architecture of DNA-PK dimers at DSBs, to trigger subsequent interactions or enzymatic reactions.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Spagnolo, Professor Laura
• Authors: Spagnolo, L., Barbeau, J., Curtin, N. J., Morris, E. P., and Pearl, L. H.
• College/School: College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Nucleic Acids Research
• Publisher: Oxford University Press
• ISSN: 0305-1048
• ISSN (Online): 1362-4962
• Copyright Holders: Copyright: © The Author(s) 2012
• First Published: First published in Nucleic Acids Research 40(9): 4168–4177
• Publisher Policy: Reproduced under a Creative Commons licence