In Cell this week, an international research team reports their identification of KIAA1018/MTMR15/FAN1, a highly conserved protein, which is "recruited to sites of DNA damage by the monoubiquitinated form of FANCD2." FAN1 depletion in human cells, the team shows, results in a hypersensitivity to interstrand crosslinks, ICL repair-related issues, and genome instability.