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| ATP activates ataxia-telangiectasia mutated (ATM) in vitro - Importance of autophosphorylation |
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| Author(s): Kozlov S, Gueven N, Keating K, Ramsay J, Lavin MF |
| Source: JOURNAL OF BIOLOGICAL CHEMISTRY Volume: 278 Issue: 11 Pages: 9309-9317 Published: MAR 14 2003 |
| Times Cited: 44 References: 62 |
| Abstract: Ataxia-telangiectasia Mutated (ATM), mutated in the human disorder ataxia-telangiectasia, is rapidly activated by DNA double strand breaks. The mechanism of activation remains unresolved, and it is uncertain whether autophosphorylation contributes to activation. We describe an in vitro immunoprecipitation system demonstrating activation of ATM kinase from unirradiated extracts by preincubation with ATP. Activation is both time- and ATP concentration-dependent, other nucleotides fail to activate ATM, and DNA is not required. ATP activation is specific for ATM since it is not observed with kinase-dead ATM, it requires Mn2+, and it is inhibited by wortmannin. Exposure of activated ATM to phosphatase abrogates activity, and repeat cycles of ATP and phosphatase treatment reveal a requirement for autophosphorylation in the activation process. Phosphopeptide mapping revealed similarities between the patterns of autophosphorylation for irradiated and ATP-treated ATM. Caffeine inhibited ATM kinase activity for substrates but did not interfere with ATM autophosphorylation. ATP failed to activate either A-T and rad3-related protein (ATR) or DNA-dependent protein kinase under these conditions, supporting the specificity for ATM. These data demonstrate that ATP can specifically induce activation of ATM by a mechanism involving autophosphorylation. The relationship of this activation to DNA damage activation remains unclear but represents a useful model for understanding in vivo activation. |
| Document Type: Article |
| Language: English |
| Reprint Address: Lavin, MF (reprint author), Queensland Inst Med Res, Canc Fund Res Unit, POB Royal Brisbane Hosp, Brisbane, Qld 4029 Australia |
Addresses:
1. Queensland Inst Med Res, Canc Fund Res Unit, Brisbane, Qld 4029 Australia
2. Univ Queensland, Dept Surg, Herston, Qld 4029 Australia
3. Mater Hosp, Queensland Radium Inst, Brisbane, Qld 4101 Australia
4. ERIX Therapeut Ltd, Cork, Ireland |
| Publisher: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA |
| Subject Category: Biochemistry & Molecular Biology |
| IDS Number: 654YF |
| ISSN: 0021-9258 |
| DOI: 10.1074/jbc.M300003200 |
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