Cao, Z.; Briola, G. R.; Ionita, C.; Streetley, J.; Walden, H. L.; Rennie, M. L.

FANCD2 is involved in the DNA Damage Response, particularly the repair of interstrand crosslinks via homologous recombination. Having recently been established to be a DNA clamp, it is still unclear if and how FANCD2 directly recruits other factors to coordinate DNA repair. Here we show that FANCD2 has a conserved acidic region that directly binds proteins involved in different aspects of DNA repair, using a combination of cryoEM, AlphaFold and biochemical reconstitution. We further identify several additional candidate interactors at this site that are involved in histone modification, and RNA processing. All of these interactors involve a short linear motif, which we refer to as a D2-interacting protein motif (DIP-box), akin to PCNA-interacting protein motifs (PIP-boxes). These data demonstrate FANCD2 is a hub for protein-protein interactions providing a structural explanation for FANCD2's central role in repair of DNA interstrand crosslinks.