FANCD2 and Fanconi anemia: In response to ICL formation, the protein products of eight FA genes assemble to form the nuclear “FA core complex” at the lesion, trigger the monoubiquitination of Fanconi Anemia Complementation Group (FANC) D2 (FANCD2) and FANCI, and then activate the FANCD2/FANCI dimer that orchestrates the coordinated recruitment of downstream proteins to repair the lesion.