It receives E1 compound ubiquitin and catalyzes its covalently binding with other proteins. Monoubiquitination is catalyzed. Mitomycin-C (MMC)-induced DNA restore. Through interaction with the E3 ubiquitin-ligase FANCL and catalytic mono-ubiquitination of FANCD2, it acts as a particular E2 ubiquitin-ligase for the Fanconi anemia complex. Here, FANCL is linked to Fanconi anemia.