PARP1
PARP1
PARP1
Fork collapse
Persistent trapping
PARP1
HRproficient
HRdeficient
HRdeficient
HRproficient
Error-prone repairGenomic instability
Error-prone repairGenomic instability
single-ended DSB
SSB
PARP1 binding
inhibited PARylation
Trapped PARP1
PARPi binding
Replication fork
PARP1
PARP1
PARP1
XRCC1
XRCC1
PARP1
PARP1
PARG
SSB
PARP1 binding
activated PARylation
Recruitment of DNA repair factors
autoPARylation-drivenPARP1 release
PAR degradationby PARG
Repair of DNA lesion
+ NAD+
Re-activation ofPARP1
No PARPi(No Trapping)
Trapping by PARPi(e.g. Olaparib, Talazoparib)