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Autophosphorylation and ATM activation: additional sites add to the complexity

Sergei V Kozlov1, Mark E Graham, Burkhard Jakob

  • 1Radiation Biology and Oncology, Queensland Institute of Medical Research, Brisbane, Queensland 4029, Australia. sergei.kozlov@qimr.edu.au

The Journal of Biological Chemistry
|December 15, 2010
PubMed

Insights

Researchers identified new ATM phosphorylation sites crucial for DNA double-strand break repair. These sites, Ser(367) and Ser(2996), are essential for ATM kinase activation and function in DNA damage response.

Area of Science:

  • Molecular Biology
  • Cellular Biology
  • Biochemistry

Background:

  • DNA double-strand breaks (DSBs) trigger complex signaling pathways for repair.
  • ATM (ataxia-telangiectasia mutated) kinase is a key regulator in the DSB response.
  • ATM activation involves autophosphorylation and recruitment to break sites by the Mre11-Rad50-Nbs1 complex.

Purpose of the Study:

  • To identify and characterize novel ATM phosphorylation sites.
  • To investigate the role of specific ATM phosphorylation sites in DNA damage signaling and cellular response.
  • To confirm conserved ATM phosphorylation sites between human and murine cells.

Main Methods:

  • Mass spectrometry to identify novel ATM phosphorylation sites.
  • Generation of phosphospecific antibodies against Ser(367) and Ser(2996).
  • Irradiation of cells to induce DNA damage and assess phosphorylation.
  • Use of ATM inhibitors and analysis of ATM-deficient cells (ataxia-telangiectasia).

Main Results:

  • Identification of Thr(1885) and Ser(2996) as new ATM phosphorylation sites.
  • Phosphorylation of Ser(367) and Ser(2996) is rapidly induced by radiation and dependent on ATM and the MRN complex.
  • Phosphorylation at Ser(367) and Ser(2996) is crucial for ATM's role in the S phase checkpoint and radioresistance.
  • Phosphorylated ATM localizes to DNA damage sites, but recruitment is independent of these specific phosphorylations.

Conclusions:

  • ATM autophosphorylation at Ser(367) and Ser(2996) plays a critical role in its activation and function.
  • These novel phosphorylation sites are essential for maintaining genomic integrity and cellular survival following DNA damage.
  • The findings underscore the importance of post-translational modifications in regulating ATM kinase activity.

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