Revised model for mechanism of action of IMiDs in PEL cells. Lenalidomide and pomalidomide trigger inconsequential degradation of neosubstrates IKZF1, IKZF3 and ZFP91. The degradation of the neosubstrate CK1α and the IKZF1- and IKZF3-independent loss of IRF4 expression upon IMiD treatment represent separate arms of IMiD toxicity.