Molecular imaging of the ATM kinase activity
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Updated: May 10, 2026
Assaying Protein Kinase Activity with Radiolabeled ATP
Published on: May 26, 2017
Terence M Williams1, Shyam Nyati, Brian D Ross
1Department of Radiation Oncology, Ohio State University, Columbus, Ohio, USA.
Purpose:
Ataxia telangiectasia mutated (ATM) is a serine/threonine kinase critical to the cellular DNA-damage response, including from DNA double-strand breaks. ATM activation results in the initiation of a complex cascade of events including DNA damage repair, cell cycle checkpoint control, and survival. We sought to create a bioluminescent reporter that dynamically and noninvasively measures ATM kinase activity in living cells and subjects.
Methods And Materials:
Using the split luciferase technology, we constructed a hybrid cDNA, ATM-reporter (ATMR), coding for a protein that quantitatively reports on changes in ATM kinase activity through changes in bioluminescence.
Results:
Treatment of ATMR-expressing cells with ATM inhibitors resulted in a dose-dependent increase in bioluminescence activity. In contrast, induction of ATM kinase activity upon irradiation resulted in a decrease in reporter activity that correlated with ATM and Chk2 activation by immunoblotting in a time-dependent fashion. Nuclear targeting improved ATMR sensitivity to both ATM inhibitors and radiation, whereas a mutant ATMR (lacking the target phosphorylation site) displayed a muted response. Treatment with ATM inhibitors and small interfering (si)RNA-targeted knockdown of ATM confirm the specificity of the reporter. Using reporter expressing xenografted tumors demonstrated the ability of ATMR to report in ATM activity in mouse models that correlated in a time-dependent fashion with changes in Chk2 activity.
Conclusions:
We describe the development and validation of a novel, specific, noninvasive bioluminescent reporter that enables monitoring of ATM activity in real time, in vitro and in vivo. Potential applications of this reporter include the identification and development of novel ATM inhibitors or ATM-interacting partners through high-throughput screens and in vivo pharmacokinetic/pharmacodynamic studies of ATM inhibitors in preclinical models.
Insights
Researchers developed a novel bioluminescent reporter to measure Ataxia Telangiectasia Mutated (ATM) kinase activity in real-time. This tool allows for noninvasive monitoring of DNA damage response in living cells and subjects.
Area of Science:
- Molecular Biology
- Biochemistry
- Cell Biology
Background:
- Ataxia Telangiectasia Mutated (ATM) is a crucial kinase in the DNA-damage response pathway.
- ATM activation initiates DNA repair, cell cycle control, and survival mechanisms.
- Accurate measurement of ATM activity is vital for understanding cellular responses to DNA damage.
Purpose of the Study:
- To develop a novel bioluminescent reporter for dynamic, noninvasive measurement of ATM kinase activity.
- To enable real-time monitoring of ATM activity in living cells and subjects.
- To facilitate drug discovery and preclinical studies involving ATM.
Main Methods:
- Utilized split luciferase technology to construct an ATM-reporter (ATMR) hybrid cDNA.
- Engineered ATMR to quantitatively report ATM kinase activity via bioluminescence changes.
- Validated reporter specificity and sensitivity using ATM inhibitors, irradiation, and siRNA knockdown.
Main Results:
- ATMR expression showed dose-dependent bioluminescence changes with ATM inhibitors.
- Irradiation-induced ATM activity decreased reporter signals, correlating with ATM/Chk2 activation.
- Reporter demonstrated efficacy in xenografted mouse models, correlating with Chk2 activity.
Conclusions:
- Developed and validated a specific, noninvasive bioluminescent reporter for real-time ATM activity monitoring.
- The ATMR reporter is applicable both in vitro and in vivo.
- Potential applications include high-throughput screening for ATM inhibitors and pharmacokinetic/pharmacodynamic studies.
