FANCD2–FANCI Complex Recognizes Double-Stranded to Single-Stranded DNA Junctions and Plays a Central Role in DNA Crosslink Repair and Replication Fork Protection

The FANCD2-FANCI protein complex is a sliding clamp that binds and diffuses on double-stranded DNA, but stalls at single-stranded to double-stranded DNA junctions, which are generated at stalled replication forks. This allows the complex to recognize sites of DNA damage and coordinate DNA repair.