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FIG 9 ES08 induces greater dissociation of corepressors from E403X mutant TRα than T3 does, but fails to recruit Gal4-TRAP220 coactivator in cellular protein interaction assays. (A) Dissociation of VP16-WT or VP16-E403X mutant TRα from GAL4-NCOR-δ with increasing concentrations (0 to 10,000 nM) of T3 or ES08. Results, shown as relative luciferase units (RLU) normalized to β-galactosidase activity, are given as the mean ± SEM of at least 5 independent experiments performed in triplicate. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001 for comparison of E403X plus T3 versus E403X plus ES08. (B) Interaction of VP16-E403X mutant TRα with different Gal4-corepressor isoform fusions in the absence of ligand (0), 1,000 nM T3, or ES08. Results from at least 5 independent experiments performed in triplicate are expressed as a percentage of WT TRα-corepressor interaction in the absence of T3. *, P < 0.05; **, P < 0.01 for comparison of E403X plus T3 versus E403X plus ES08. (C) Inability of VP16-E403X mutant TRα (red line) to recruit GAL4-TRAP220 coactivator fusion over a range (0 to 10,000 nM) of T3 or ES08 concentrations. The data are expressed as fold induction relative to cells transfected with Gal4-TRAP220 and VP16 alone and are shown as the mean ± SEM of at least 5 independent experiments each performed in triplicate.