FIGURE 1.

SENP1 abolishes MG-132-induced formation of GFP-Nrf2-containing nuclear aggregates. HepG2 cells grown in MEM were transfected with 1.5 μg of pEGFP-Nrf2. Some cultures were also transfected with 1 μg of pFLAG (vector) (columns 1 and 2) or 1 μg of expression plasmid for SENP1 (column 3) or SENP1mt (column 4). After 24 h, some cultures (lanes 2–4) were treated for 4 h with MG-132 (final concentration, 10 μm). All cells were then harvested and fixed as described under “Experimental Procedures.” This figure is representative of four experiments. Scale bars, 5 μm. Representative Western blot of SENP1 is shown. GAPDH, loading control. Anti-SENP1 antibody (catalog no. 2887-1) was obtained from Epitomics Inc. The number of GFP-Nrf2-containing nuclear aggregates for each treatment group (n = 23–41 cells) is shown in the histogram. Values plotted are means ± S.E. One-way analysis of variance was performed with Tukey multiple comparison test. *** Statistically different (p < 0.0001).