Figure 7.
ATR inhibits SMARCAL1. ATRIP binding to the 70N domain of RPA recruits ATR to replication forks. The SMARCAL1 RBD binds RPA32C to bring SMARCAL1 to replication forks. Once SMARCAL1 binds to the forked DNA via its ATPase and HARP domains, it becomes a substrate for ATR phosphorylation. Phosphorylation within the linker between the ATPase domains inhibits SMARCAL1 activity.