(D) Expression of FLAG-FBW7α enhanced HA-SOX9-WT protein turnover, which can be attenuated with addition of 10 µM MG-132 (MG) in HEK293 cells. By contrast, forced expression of FLAG-FBW7α did not enhance HA-SOX9-T236A and -T236A/T240A protein turnover over the course of 4 hours protein chase. Protein loading for each sample was indicated by the level of β-actin protein. The set of blots shown is representative from 4 independent experiments. 