Figure 9.

Effects mediated by compound 20 are CK1δ-specific but not mutant-specific. (a) MTT viability assays have been performed by treating parental HeLa cells, HeLa CK1δ^−/−, or HeLa CK1δ^+/+ cells with 5 μM of compound 20 or DMSO as control for 48 h. Cell viability of treated cells has been normalized toward the viability of DMSO-treated cells. Results are presented as mean values of experiments performed in triplicate. Error bars represent the SD. (b–d) Cell viability of HeLa CK1δ^−/− cells expressing CK1δ^WT, CK1δ^T67S (b), CK1δ^R127Q (c), or CK1δ^R168H (d) has been determined by MTT viability assay after treatment with compound 20 (5 μM) or DMSO as control for 48 h. Cell viability of treated cells has been normalized toward the viability of DMSO-treated cells. Results are presented as mean values of experiments performed in triplicate. Error bars represent the SD. Statistical analysis was done by performing two-way ANOVA using following levels of significance: *** p ≤ 0.001; **** p ≤ 0.0001; ns, not significant. Abbreviations: H, histidine; Q, glutamine; R, arginine; S, serine; T, threonine; TV, transcription variant; WT, wild type.