Figure 3.

Nuclear uptake of GSH as a function of Bcl-2 protein concentration in isolated nuclei. To determine the relationship between uptake of GSH and Bcl-2 protein expression, isolated nuclei from HeLa/Tet-Bcl-2 cells were incubated with [³H]GSH in TKN buffer for 45 min as described previously (9). To obtain varying levels of Bcl-2, cells were exposed to titrated levels of Tet before nuclei isolation. Nuclei were then processed for Western blot analysis of Bcl-2 or incubated with radiolabeled GSH. (A) Increased GSH uptake was observed in nuclei that expressed elevated levels of Bcl-2. (B) Verification of Bcl-2 protein levels observed in isolated nuclei by Western blot analysis. Error bars represent SE from three independent experiments repeated with similar results.