Aim of the experiments was to identify endogenously SUMO2/3 modified proteins in HEK293 cells. Cells were treated with dexamethasone (dex) or vehicle (etoh) and with heatshock (+43C, HS) or normal growth temperature (+37C, non-HS). Cells were induced with tetracycline to express BirA*-GR (glucocorticoid receptor) to express GR at sufficient levels to assess effect of GR activation on protein SUMOylation.