DNA-dependent protein kinase (Ku protein-p350 complex) assembles on double-stranded DNA.

Suwa, Akira; Hirakata, Michito; Takeda, Yoshihiko; Jesch, Stephen A.; Mimori, Tsuneyo; Hardin, John A.

doi:10.1073/pnas.91.15.6904

Cited by 161 publications

(127 citation statements)

References 35 publications

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“…It is also possible that yeast Ku homologues compete for binding to DNA-PKcs. Alternatively, the Ku heterodimer may first have to bind broken DNA before it can associate with DNA-PKcs (this is a point of controversy) (5,38). It would be difficult to artificially introduce broken DNA ends into yeast cells, and they might be repaired or cause cell death.…”

Section: Discussionmentioning

confidence: 99%

Defining the Minimal Domain of Ku80 for Interaction with Ku70

Osipovich

Durum

Muegge

1997

Journal of Biological Chemistry

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The Ku protein has a critical function in the repair of double-strand DNA breaks induced for example by ionizing radiation or during VDJ recombination. Ku serves as the DNA-binding subunit of the DNA-dependent kinase and is a heterodimeric protein composed of 80-and 70-kDa subunits. We used the two-hybrid system to analyze the interaction domains of the Ku subunits and to identify possible additional partners for Ku. Screening a human cDNA library with the Ku heterodimer did not reveal any novel partners. Screening with the individual subunits, we detected only Ku70 clones interacting with Ku80 and only Ku80 clones interacting with Ku70, indicating that these are the primary partners for one another. Ku80 and Ku70 formed only heterodimers and did not homodimerize. Ku80 was restricted to interacting with just one Ku70 molecule at a time. The minimal functional interaction domain of Ku80 that interacted with Ku70 was defined. It consisted of a 28-amino acid region extending from amino acid 449 to 477. This region was crucial for interaction with Ku70, since mutation within this critical site at amino acids 453 and 454 abrogated the ability to interact with Ku70. We furthermore verified that the same region is crucial for interaction with Ku70 using in vitro co-translation of both subunits followed by an immunoprecipitation with anti-Ku70 antibodies. This interaction domain of Ku80 does not contain any motif previously recognized in protein-protein interactions.

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Section: Discussionmentioning

confidence: 99%

Defining the Minimal Domain of Ku80 for Interaction with Ku70

Osipovich

Durum

Muegge

1997

Journal of Biological Chemistry

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“…Therefore, it is possible that the p53 population not engaged in transcriptional regulation could exert functions other than induction of growth arrest or apoptosis, and directly participate in processes of DNA repair via its various biochemical activities described above. The exonuclease activity, for example, could be involved in repair processes such as DSB repair, which is thought to require DNA helicases, like the Ku autoantigen (Suwa et al, 1994;Tuteja et al, 1994), and exonucleases. Furthermore, p53 might act as an external proofreader for errors produced by cellular DNA polymerases involved in DNA replication and DNA repair also under DNA damage conditions.…”

Section: Possible Functions Of the P53 Exonuclease Activitymentioning

confidence: 99%

Maintenance of genomic integrity by p53: complementary roles for activated and non-activated p53

Albrechtsen

Dornreiter

Grosse³

et al. 1999

Oncogene

167

121

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“…Under these conditions, the protein-protein interaction of HSF1 with both Ku protein and DNA-PKcs may be critical. Ku protein and DNA-PKcs do not ordinarily bind one another in the absence of DNA breaks (35,38). Because HSF1 is capable of binding both components in the absence of DNA, it may provide a mechanism for assembling the two components of DNA-PK into an active complex in the absence of DNA damage.…”

Section: Stimulation Of Dna-pk Activity By Hsf1-(1-450) and Mutant Dementioning

confidence: 99%

Heat Shock Transcription Factor 1 Binds Selectively in Vitro to Ku Protein and the Catalytic Subunit of the DNA-dependent Protein Kinase

Huang

Nueda

Yoo

et al. 1997

Journal of Biological Chemistry

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Heat shock transcription factor 1 (HSF1) functions as the master regulator of the heat shock response in eukaryotes. We have previously shown that, in addition to its role as a transcription factor, HSF1 stimulates the activity of the DNA-dependent protein kinase (DNA-PK). DNA-PK is composed of two components: a 460-kDa catalytic subunit and a 70-and 86-kDa heterodimeric regulatory component, also known as the Ku protein. We report here that HSF1 binds specifically to each of the two components of DNA-PK. Binding occurs in the absence of DNA. The complex with the Ku protein is stable and forms at a stoichiometry close to unity between the Ku protein heterodimer and the active HSF1 trimer. The binding is blocked by antibodies against HSF1. Our results show that HSF1 also binds directly, but more weakly, to the catalytic subunit of DNA-PK. Both interactions are dependent on a specific region within the HSF1 regulatory domain. This sequence is necessary but not sufficient for HSF1 stimulation of DNA-PK activity. The ability of HSF1 to interact with both components of DNA-PK provides a potential mechanism for the activation of DNA-PK in response to heat and other forms of stress.

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DNA-dependent protein kinase (Ku protein-p350 complex) assembles on double-stranded DNA.

Cited by 161 publications

References 35 publications

Defining the Minimal Domain of Ku80 for Interaction with Ku70

Defining the Minimal Domain of Ku80 for Interaction with Ku70

Maintenance of genomic integrity by p53: complementary roles for activated and non-activated p53

Heat Shock Transcription Factor 1 Binds Selectively in Vitro to Ku Protein and the Catalytic Subunit of the DNA-dependent Protein Kinase

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