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| Subject Categories: Signal Transduction | Genome Stability & Dynamics |
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| The EMBO Journal
(2006) 25, 3504–3514, doi:10.1038/sj.emboj.7601231 Published online 13 July 2006 |
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| Involvement of novel autophosphorylation sites in ATM activation |
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| Sergei V Kozlov1, Mark E Graham2, Cheng Peng1, Philip Chen1, Phillip J Robinson2 and Martin F Lavin1, 3 |
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1 The Queensland Institute of Medical Research, Post Office Royal Brisbane Hospital, Herston, Brisbane, Queensland, Australia 2 Cell Signalling Unit, Children's Medical Research Institute, Westmead, New South Wales, Australia 3 Central Clinical Division, University of Queensland, PO Royal Brisbane Hospital, Herston, Queensland, Australia To whom correspondence should be addressed Martin F Lavin, The Queensland Cancer Fund Research Unit, The Queensland Institute of Medical Research, Post Office Royal Brisbane Hospital, Herston, Brisbane, Queensland 4029, Australia. Tel.: +61 7 3362 0335; Fax: +61 7 3362 0106; E-mail: martinl@qimr.edu.au Received 8 November 2005; Accepted 20 June 2006; Published online 13 July 2006. |
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| Abstract |
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| ATM kinase plays a central role in signaling DNA double-strand breaks to cell cycle checkpoints and to the DNA repair machinery. Although the exact mechanism of ATM activation remains unknown, efficient activation requires the Mre11 complex, autophosphorylation on S1981 and the involvement of protein phosphatases and acetylases. We report here the identification of several additional phosphorylation sites on ATM in response to DNA damage, including autophosphorylation on pS367 and pS1893. ATM autophosphorylates all these sites in vitro in response to DNA damage. Antibodies against phosphoserine 1893 revealed rapid and persistent phosphorylation at this site after in vivo activation of ATM kinase by ionizing radiation, paralleling that observed for S1981 phosphorylation. Phosphorylation was dependent on functional ATM and on the Mre11 complex. All three autophosphorylation sites are physiologically important parts of the DNA damage response, as phosphorylation site mutants (S367A, S1893A and S1981A) were each defective in ATM signaling in vivo and each failed to correct radiosensitivity, genome instability and cell cycle checkpoint defects in ataxia-telangiectasia cells. We conclude that there are at least three functionally important radiation-induced autophosphorylation events in ATM. |
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| Keywords: ATM, autophosphorylation, DNA damage signaling, phosphorylation sites mapping |
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