FIGURE 9.

Exogenous WT B56α localizes to the nuclei and mitochondria and promotes sensitivity to etoposide. A, subcellular fractionation studies were performed using 4 × 10⁷ cells to isolate nuclei and mitochondria from REH cells transfected with control plasmid (GFP), WT B56α (WT), or S28A B56α (S28A). Western blot analysis using 40 μg of protein from total protein, nuclear protein, and mitochondrial protein was performed using antibodies against HA, PKR, and appropriate loading control (tubulin for total protein, lamin for nuclear protein, and COX IV for mitochondrial protein). B, 0.5 × 10⁶ cells were treated with 0.1 or 1 μm etoposide for 24 h. Viability was determined by trypan blue exclusion. Error bars represent the mean ± S.D. from three separate experiments. *, statistically significant differences from cell viability in untreated REH cells transfected with (p < 0.05, standard t test).