ATM safeguards DNA replication by restraining pathological repriming at endogenous base lesions.
Poly(ADP-ribose) polymerase inhibitors (PARPi) exploit homologous recombination (HR) deficiency in BRCA1/2-mutant cancers to induce synthetic lethality. PARPi also kill ataxia telangiectasia-mutated (ATM)-deficient cells, but the underlying mechanism has remained unclear. Here, we define the mechanism of PARPi cytotoxi...