UBE2T/FANCL-IN-1 is a potent inhibitor of UBE2T/FANCL-mediated FANCD2 monoubiquitylation that sensitizes cells to the DNA cross-linking agent, Carboplatin.In Vitro: UBE2T/FANCL-IN-1 (CU2) completely inhibits the ubiquitylation of GST-FANCLRING at 100 μM. UBE2T/FANCL-IN-1 (500 μM) reduced the level of mUb-FANCD2 in response to HU treatment. UBE2T/FANCL-IN-1 (500 μM) also reducesthe level of mUb-FANCD2 generated in response to Cisplatin (10 μM) treatment for 6, 12, and 24 hours. The combination of 250 μM UBE2T/FANCL-IN-1 with 15 μM carboplatin led to an even more pronounced decrease in cell proliferation/growth, with the cells being <50% confluent after 8 days.