The FANCD2 CUE domain is required for efficient interaction with FANCI. (A) WCLs from FA-D2 cells reconstituted with WT or mutant FANCD2 were immunoprecipitated with antibodies against FANCD2 or mouse IgG. Bound proteins were resolved and immunoblotted with antibodies against FANCD2 and FANCI. (B) WCLs from COS-7 cells transfected with WT or mutant FANCD2-V5 were immunoprecipitated with antibodies against V5 or mouse IgG. Bound proteins were resolved and immunoblotted with antibodies against V5 and FANCI.