Fig. 2.

In vitro SUMOylation of TRα and TRβ. a-c SUMOylation of TRα by SUMO-1 (S1) (a), SUMO-2 (S2) (b), and SUMO-3 (S3) (c) was identified. TRα wild-type (wt), the indicated single point mutants, a double mutant K281/387R, and a triple mutant K281/286/387R were applied to an in vitro SUMOylation assay. SUMOylated and unmodified TR were detected by Western blot analysis and are indicated by arrows. d-f SUMOylation of TRβ by SUMO-1 (S1) (d), SUMO-2 (S2) (e), and SUMO-3 (S3) (f) was also recorded. TRβ wt and the indicated single point mutants were applied to an in vitro SUMOylation assay and detected by Western blot analysis and quantified. Numbers indicate the quantification of the upper (SUMOylated) relative to the lower (unmodified) band. SUMOylated and unmodified TR are denoted by arrows.