Repair of ionizing radiation-induced DNA double-strand breaks by non-homologous end-joining

Mahaney, Brandi L.; Meek, Katheryn; Lees‐Miller, Susan P.

doi:10.1042/bj20080413

Cited by 605 publications

(645 citation statements)

References 181 publications

Supporting

Mentioning

626

Contrasting

Unclassified

Order By: Relevance

“…DNA-dependent protein kinase (DNA-PK) is a serine/threonine kinase composed of a catalytic subunit (DNA-PKcs) and a heterodimeric complex of Ku70 and Ku86, which binds to the two DNA ends in a ring conformation. This event subsequently activates DNA-PKcs, which promotes the ligation of DNA ends in the presence of other components of the NHEJ-repair machinery (Mahaney et al, 2009). Modulation of DNA-PK activity is not exclusively regulated by the coordinated assembly of Ku and DNA-PKcs on DNA ends.…”

Section: Introductionmentioning

confidence: 99%

Regulation of DNA-dependent protein kinase by protein kinase CK2 in human glioblastoma cells

2010

View full text Add to dashboard Cite

The DNA-dependent protein kinase (DNA-PK) is a nuclear serine/threonine protein kinase composed of a large catalytic subunit (DNA-PKcs) and a heterodimeric DNA-targeting subunit Ku. DNA-PK is a major component of the nonhomologous end-joining pathway of DNA double-strand breaks repair. Although DNA-PK has been biochemically characterized in vitro, relatively little is known about its functions in the context of DNA repair and how its kinase activity is precisely regulated in vivo. Here, we report that cellular depletion of the individual catalytic subunits of protein kinase CK2 by RNA interference leads to significant cell death in M059K human glioblastoma cells expressing DNA-PKcs, but not in their isogenic counterpart, that is M059J cells, devoid of DNA-PKcs. The lack of CK2 results in enhanced DNA-PKcs activity and strongly inhibits DNA damageinduced autophosphorylation of DNA-PKcs at S2056 as well as repair of DNA double-strand breaks. By the application of the in situ proximity ligation assay, we show that CK2 interacts with DNA-PKcs in normal growing cells and that the association increases upon DNA damage. These results indicate that CK2 has an important role in the modulation of DNA-PKcs activity and its phosphorylation status providing important insights into the mechanisms by which DNA-PKcs is regulated in vivo.

show abstract

Section: Introductionmentioning

confidence: 99%

Regulation of DNA-dependent protein kinase by protein kinase CK2 in human glioblastoma cells

2010

View full text Add to dashboard Cite

show abstract

“…7 This pathway depends on the activity of a PI3K-like DNA-dependent protein kinase (DNA-PK), which consists of DNA-PK catalytic subunit (DNA-PKcs), KU70 and KU80 subunits of the KU heterodimer, and on the activity of DNA ligase 4 and its associated cofactor XRCC4. 8 Similarly to ATM, DNA-PK preferentially recognizes and phosphorylates a S/TQ motif. 8 In this study, we addressed DDR signaling and radioresistance of TD astrocytes, which are the predominant cell type in the mammalian brain and have key roles in brain physiology, development and plasticity.…”

mentioning

confidence: 99%

“…8 Similarly to ATM, DNA-PK preferentially recognizes and phosphorylates a S/TQ motif. 8 In this study, we addressed DDR signaling and radioresistance of TD astrocytes, which are the predominant cell type in the mammalian brain and have key roles in brain physiology, development and plasticity. 9 Glial cells like astrocytes, but also neurons, derive from neural stem cells (NSC) residing in specific brain areas.…”

mentioning

confidence: 99%

Terminally differentiated astrocytes lack DNA damage response signaling and are radioresistant but retain DNA repair proficiency

2011

View full text Add to dashboard Cite

The impact and consequences of damage generation into genomic DNA, especially in the form of DNA double-strand breaks, and of the DNA-damage response (DDR) pathways that are promptly activated, have been elucidated in great detail. Most of this research, however, has been performed on proliferating, often cancerous, cell lines. In a mammalian body, the majority of cells are terminally differentiated (TD), and derives from a small pool of self-renewing somatic stem cells. Here, we comparatively studied DDR signaling and radiosensitivity in neural stem cells (NSC) and their TD-descendants, astrocytes -the predominant cells in the mammalian brain. Astrocytes have important roles in brain physiology, development and plasticity. We discovered that NSC activate canonical DDR upon exposure to ionizing radiation. Strikingly, astrocytes proved radioresistant, lacked functional DDR signaling, with key DDR genes such as ATM being repressed at the transcriptional level. Nevertheless, astrocytes retain the expression of non-homologous end-joining (NHEJ) genes and indeed they are DNA repair proficient. Unlike in NSC, in astrocytes DNA-PK seems to be the PI3K-like protein kinase responsible for cH2AX signal generation upon DNA damage. We also demonstrate the lack of functional DDR signaling activation in vivo in astrocytes of irradiated adult mouse brains, although adjacent neurons activate the DDR.

show abstract

“…Alternatively, the DSB ends may be bound by the KU70/ KU80 heterodimer, which is required for the alternative DSB repair pathway, non-homologous end joining (NHEJ); this binding may recruit another PIKK family kinase, DNA-PK, and subsequently activate it (Gottlieb and Jackson, 1993;Mahaney et al, 2009). These kinases, particularly ATM, phosphorylate serine 139 of H2AX (to γ-H2AX) and initiate the chromatin response to DNA damage (Rogakou et al, 1998;Downs et al, 2004;Ataian and Krebs, 2006;Bao, 2011).…”

Section: Introductionmentioning

confidence: 99%

Chromatin modification and NBS1: their relationship in DNA double-strand break repair

2015

View full text Add to dashboard Cite

The importance of chromatin modification, including histone modification and chromatin remodeling, for DNA double-strand break (DSB) repair, as well as transcription and replication, has been elucidated. Phosphorylation of H2AX to γ-H2AX is one of the first responses following DSB detection, and this histone modification is important for the DSB damage response by triggering several events, including the accumulation of DNA damage response-related proteins and subsequent homologous recombination (HR) repair. The roles of other histone modifications such as acetylation, methylation and ubiquitination have also been recently clarified, particularly in the context of HR repair. NBS1 is a multifunctional protein that is involved in various DNA damage responses. Its recently identified binding partner RNF20 is an E3 ubiquitin ligase that facilitates the monoubiquitination of histone H2B, a process that is crucial for recruitment of the chromatin remodeler SNF2h to DSB damage sites. Evidence suggests that SNF2h functions in HR repair, probably through regulation of end-resection. Moreover, several recent reports have indicated that SNF2h can function in HR repair pathways as a histone remodeler and that other known histone remodelers can also participate in DSB damage responses. On the other hand, information about the roles of such chromatin modifications and NBS1 in non-homologous end joining (NHEJ) repair of DSBs and stalled fork-related damage responses is very limited; therefore, these aspects and processes need to be further studied to advance our understanding of the mechanisms and molecular players involved.

show abstract

Repair of ionizing radiation-induced DNA double-strand breaks by non-homologous end-joining

Cited by 605 publications

References 181 publications

Regulation of DNA-dependent protein kinase by protein kinase CK2 in human glioblastoma cells

Regulation of DNA-dependent protein kinase by protein kinase CK2 in human glioblastoma cells

Terminally differentiated astrocytes lack DNA damage response signaling and are radioresistant but retain DNA repair proficiency

Chromatin modification and NBS1: their relationship in DNA double-strand break repair

Contact Info

Product

Resources

About