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A mechanism for DNA-PK activation requiring unique contributions from each strand of a DNA terminus and implications for microhomology-mediated nonhomologous DNA end joining

DNA-dependent protein kinase (DNA-PK) is an essential component of the nonhomologous end joining pathway (NHEJ), responsible for the repair of DNA double-strand breaks. Ku binds a DSB and recruits the catalytic subunit, DNA-PKcs, where it is activated once the kinase is bound to the DSB. The precise...

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Autores principales: Pawelczak, Katherine S., Turchi, John J.
Formato: Texto
Lenguaje:English
Publicado: Oxford University Press 2008
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2475626/
https://www.ncbi.nlm.nih.gov/pubmed/18515838
http://dx.doi.org/10.1093/nar/gkn344
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author Pawelczak, Katherine S.
Turchi, John J.
author_facet Pawelczak, Katherine S.
Turchi, John J.
author_sort Pawelczak, Katherine S.
collection PubMed
description DNA-dependent protein kinase (DNA-PK) is an essential component of the nonhomologous end joining pathway (NHEJ), responsible for the repair of DNA double-strand breaks. Ku binds a DSB and recruits the catalytic subunit, DNA-PKcs, where it is activated once the kinase is bound to the DSB. The precise mechanism by which DNA activates DNA-PK remains unknown. We have investigated the effect of DNA structure on DNA-PK activation and results demonstrate that in Ku-dependent DNA-PKcs reactions, DNA-PK activation with DNA effectors containing two unannealed ends was identical to activation observed with fully duplex DNA effectors of the same length. The presence of a 6-base single-stranded extension resulted in decreased activation compared to the fully duplex DNA. DNA-PK activation using DNA effectors with compatible termini displayed increased activity compared to effectors with noncompatible termini. A strand orientation preference was observed in these reactions and suggests a model where the 3′ strand of the terminus is responsible for annealing and the 5′ strand is involved in activation of DNA-PK. These results demonstrate the influence of DNA structure and orientation on DNA-PK activation and provide a molecular mechanism of activation resulting from compatible termini, an essential step in microhomology-mediated NHEJ.
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spelling pubmed-24756262008-07-21 A mechanism for DNA-PK activation requiring unique contributions from each strand of a DNA terminus and implications for microhomology-mediated nonhomologous DNA end joining Pawelczak, Katherine S. Turchi, John J. Nucleic Acids Res Nucleic Acid Enzymes DNA-dependent protein kinase (DNA-PK) is an essential component of the nonhomologous end joining pathway (NHEJ), responsible for the repair of DNA double-strand breaks. Ku binds a DSB and recruits the catalytic subunit, DNA-PKcs, where it is activated once the kinase is bound to the DSB. The precise mechanism by which DNA activates DNA-PK remains unknown. We have investigated the effect of DNA structure on DNA-PK activation and results demonstrate that in Ku-dependent DNA-PKcs reactions, DNA-PK activation with DNA effectors containing two unannealed ends was identical to activation observed with fully duplex DNA effectors of the same length. The presence of a 6-base single-stranded extension resulted in decreased activation compared to the fully duplex DNA. DNA-PK activation using DNA effectors with compatible termini displayed increased activity compared to effectors with noncompatible termini. A strand orientation preference was observed in these reactions and suggests a model where the 3′ strand of the terminus is responsible for annealing and the 5′ strand is involved in activation of DNA-PK. These results demonstrate the influence of DNA structure and orientation on DNA-PK activation and provide a molecular mechanism of activation resulting from compatible termini, an essential step in microhomology-mediated NHEJ. Oxford University Press 2008-07 2008-05-31 /pmc/articles/PMC2475626/ /pubmed/18515838 http://dx.doi.org/10.1093/nar/gkn344 Text en © 2008 The Author(s) http://creativecommons.org/licenses/by-nc/2.0/uk/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Nucleic Acid Enzymes
Pawelczak, Katherine S.
Turchi, John J.
A mechanism for DNA-PK activation requiring unique contributions from each strand of a DNA terminus and implications for microhomology-mediated nonhomologous DNA end joining
title A mechanism for DNA-PK activation requiring unique contributions from each strand of a DNA terminus and implications for microhomology-mediated nonhomologous DNA end joining
title_full A mechanism for DNA-PK activation requiring unique contributions from each strand of a DNA terminus and implications for microhomology-mediated nonhomologous DNA end joining
title_fullStr A mechanism for DNA-PK activation requiring unique contributions from each strand of a DNA terminus and implications for microhomology-mediated nonhomologous DNA end joining
title_full_unstemmed A mechanism for DNA-PK activation requiring unique contributions from each strand of a DNA terminus and implications for microhomology-mediated nonhomologous DNA end joining
title_short A mechanism for DNA-PK activation requiring unique contributions from each strand of a DNA terminus and implications for microhomology-mediated nonhomologous DNA end joining
title_sort mechanism for dna-pk activation requiring unique contributions from each strand of a dna terminus and implications for microhomology-mediated nonhomologous dna end joining
topic Nucleic Acid Enzymes
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2475626/
https://www.ncbi.nlm.nih.gov/pubmed/18515838
http://dx.doi.org/10.1093/nar/gkn344
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