Ablation of UBE2G1 significantly diminished the degradation of IKFZ1 (Figure 3A, and Figure 3—figure supplement 1A,B), IKZF3 (Figure 3A, and Figure 3—figure supplement 1A,B) and ZFP91 (Figure 7B, and Figure 7—figure supplement 1B,D) by LEN, POM, and CC-220, as well as CK1α degradation (Figure 7B, and Figure 7—figure supplement 1B,D) by LEN in OPM2, DF15 and MM1S myeloma cells. Here, ZFP91 is linked to plasma cell myeloma.