The effect of CRBN mutations in a heterozygous model. (A) GI50 cell viability measurements for the CRBN^WT/WT cell line (WT plasmid overexpression) and each cell line with heterozygous CRBN (mutated CRBN overexpression). The corresponding CRBN^KO clone 1 homozygous mutation GI50 curve from Figure 2A has been added to each graph (gray) only to aid in the visual comparison between heterozygous and homozygous mutations. The color of the title for each graph denotes the effect on cell viability associated with each mutation in its homozygous state, where green is associated with reduction in cell viability comparable with parental MM1.s, red denotes no reduction in cell viability, and orange highlights the mutations whose presence leads to partial reduction in cell viability. Cells were treated with DMSO or increasing concentrations of Pom (maximum concentration 8 μM) and Mezi (maximum concentration 1 μM) for 5 days. Cell viability was determined using the CellTiter-Blue assay and expressed as a % of DMSO control. Results are the mean ± SEM of n = 3 biological replicates.