Protocol for quantifying PARP inhibitor-induced changes in PARP1 dynamics and activity through live-cell imaging

Poly(ADP-ribose) polymerase 1 (PARP1) is a crucial DNA repair protein and a target of PARP inhibitors (PARPi), which suppress its catalytic activity while also altering its association with damaged chromatin. Here, we present a live-cell imaging protocol for obtaining high-quality kinetics of fluorescently labeled PARP1 and poly(ADP-ribose) (PAR)-binding proteins at micro-irradiation-induced DNA damage sites in untreated and PARPi-treated cells. This approach can be easily adapted to other DNA repair proteins to gain insight into the mechanism of action of diverse DNA repair-targeting drugs. For complete details on the use and execution of this protocol, please refer to Kanev et al.¹.