Fig. 6
From: Non-enzymatic roles of human RAD51 at stalled replication forks
Model depicting role of RAD51 at stalled replication forks. RAD51 binds to a stalled replication fork and stabilizes it by preventing extensive ssDNA formation. Proteins such as SMARCL1 and FBH1 promote replication fork regression resulting in the formation of the chicken foot structure. DNA2 resects the middle toe providing a substrate for RAD51 strand exchange-dependent fork restart. DNA2 also promotes degradation of nascent strands after fork regression in cells expressing hsRAD51-WT or hsRAD51-II3A (not depicted). In RAD51-depleted cells (RAD51 KD), the replication fork contains excess ssDNA due to uncoupling (Blue Box). hsRAD51-II3A is able to prevent MRE11-degradation by binding directly to the middle toe. hsRAD51-II3A is unable to restart the fork via strand exchange activity resulting in trapped replication intermediate that often consists of a one-ended DSB formed by MUS81-dependent cleavage of a reversed fork. The one-ended DSB formed requires RAD51 strand exchange activity to repair the break and reinstate the replication fork
