Caffeine Inhibits Checkpoint Responses without Inhibiting the Ataxia-Telangiectasia-mutated (ATM) and ATM- and Rad3-related (ATR) Protein Kinases.

Presents a study indicating that multiple ataxia-telangiectasia-mutated (ATM) and ATM- and Rad3-related substrates including CHK1 and -2 are hyperphosphorylated in cells treated with caffeine and genotoxic agents such as hydroxyurea or ionizing radiation. Role of ATM-ATR in the regulation of cell cycle checkpoints by phosphorylating multiple substrates; Use of caffeine to study ATM and ATR signaling; Ability of caffeine to prevent phosphorylation of ATM and ATR substrates.