MDM2 and leukemia: As expected, MMRi62 increased ubiquitinated species of MDM2B and MDM4 (Figure 3E, smearing ladders of protein bands above MDM2B or MDM4 bands), which is consistent with the result that only MMRi62 induced proteasomal degradation of MDM4 and MDM2 proteins in leukemia cells (Figure 3A).