UBE2N and acute myeloid leukemia: In acute myeloid leukemia, the ubiquitin-conjugating enzyme E2 N (UBE2N) stabilizes K63-linked chain proteins to safeguard them against immunoproteasome-dependent degradation; inhibition of this enzyme preferentially down-regulates immunoproteasome-positive acute myeloid leukemia (AML) and demonstrates the capacity of the ubiquitin–IP axis in maintaining leukemic proteostasis (81).