Figure 6. A branched model of the FA pathway.
Upon replication stress, the FA core complex monoubiquitinates FANCD2/I to recruit nucleases and promote homologous recombination. FAAP20 stabilizes the FA core complex. The FAAP20-containing FA core complex is also required for efficient Rev1 foci assembly where the ubiquitin-binding property of FAAP20 contributes to stabilizing the PCNA-associated Rev1 complex at the stalled replication fork to direct lesion bypass. FAAP20-Rev1 interaction may be further enhanced by uncharacterized interaction.