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Distinct functional domains of Nbs1 modulate the timing and magnitude of ATM activation after low doses of ionizing radiation.

Publication ,  Journal Article
Horejsí, Z; Falck, J; Bakkenist, CJ; Kastan, MB; Lukas, J; Bartek, J
Published in: Oncogene
April 15, 2004

The ATM kinase is a tumour suppressor and a key activator of genome integrity checkpoints in mammalian cells exposed to ionizing radiation (IR) and other insults that elicit DNA double-strand breaks (DSBs). In response to IR, autophosphorylation on serine 1981 causes dissociation of ATM dimers and initiates cellular ATM kinase activity. Here, we show that the kinetics and magnitude of ATM Ser1981 phosphorylation after exposure of human fibroblasts to low doses (2 Gy) of IR are altered in cells deficient in Nbs1, a substrate of ATM and a component of the MRN (Mre11-Rad50-Nbs1) complex involved in processing/repair of DSBs and ATM-dependent cell cycle checkpoints. Timely phosphorylation of both ATM Ser1981 and the ATM substrate Smc1 after IR were rescued via retrovirally mediated reconstitution of Nbs1-deficient cells by wild-type Nbs1 or mutants of Nbs1 defective in the FHA domain or nonphosphorylatable by ATM, but not by Nbs1 lacking the Mre11-interaction domain. Our data indicate that apart from its role downstream of ATM in the DNA damage checkpoint network, the MRN complex serves also as a modulator/amplifier of ATM activity. Although not absolutely required for ATM activation, the MRN nuclease complex may help reach the threshold activity of ATM necessary for optimal genome maintenance and prevention of cancer.

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Published In

Oncogene

DOI

ISSN

0950-9232

Publication Date

April 15, 2004

Volume

23

Issue

17

Start / End Page

3122 / 3127

Location

England

Related Subject Headings

  • Tumor Suppressor Proteins
  • Radiation, Ionizing
  • Protein Serine-Threonine Kinases
  • Phosphoserine
  • Phosphorylation
  • Oncology & Carcinogenesis
  • Nuclear Proteins
  • Neoplasms
  • Kinetics
  • Humans
 

Citation

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Horejsí, Z., Falck, J., Bakkenist, C. J., Kastan, M. B., Lukas, J., & Bartek, J. (2004). Distinct functional domains of Nbs1 modulate the timing and magnitude of ATM activation after low doses of ionizing radiation. Oncogene, 23(17), 3122–3127. https://doi.org/10.1038/sj.onc.1207447
Horejsí, Zuzana, Jacob Falck, Christopher J. Bakkenist, Michael B. Kastan, Jiri Lukas, and Jiri Bartek. “Distinct functional domains of Nbs1 modulate the timing and magnitude of ATM activation after low doses of ionizing radiation.Oncogene 23, no. 17 (April 15, 2004): 3122–27. https://doi.org/10.1038/sj.onc.1207447.
Horejsí Z, Falck J, Bakkenist CJ, Kastan MB, Lukas J, Bartek J. Distinct functional domains of Nbs1 modulate the timing and magnitude of ATM activation after low doses of ionizing radiation. Oncogene. 2004 Apr 15;23(17):3122–7.
Horejsí, Zuzana, et al. “Distinct functional domains of Nbs1 modulate the timing and magnitude of ATM activation after low doses of ionizing radiation.Oncogene, vol. 23, no. 17, Apr. 2004, pp. 3122–27. Pubmed, doi:10.1038/sj.onc.1207447.
Horejsí Z, Falck J, Bakkenist CJ, Kastan MB, Lukas J, Bartek J. Distinct functional domains of Nbs1 modulate the timing and magnitude of ATM activation after low doses of ionizing radiation. Oncogene. 2004 Apr 15;23(17):3122–3127.

Published In

Oncogene

DOI

ISSN

0950-9232

Publication Date

April 15, 2004

Volume

23

Issue

17

Start / End Page

3122 / 3127

Location

England

Related Subject Headings

  • Tumor Suppressor Proteins
  • Radiation, Ionizing
  • Protein Serine-Threonine Kinases
  • Phosphoserine
  • Phosphorylation
  • Oncology & Carcinogenesis
  • Nuclear Proteins
  • Neoplasms
  • Kinetics
  • Humans