Figure 4.

Bcl-2 overexpression does not affect the pH of the ER. ER pH was measured by directly exciting at 480 nm the pH-dependent EYFP contained within the cameleon probe and measuring its fluorescence emission at 535 nm. HEK-293 cells cotransfected with Cam4-ER and hBcl-2 or control vector were used. (A) Time-course experiment showing the effect of TG and ionomycin (iono) on ER pH and the subsequent calibration with 130 mM KCl + 10 μM nigericin (nig) at pH 7.6 and 6.3. (B) pH values measured in the ER of control and hBcl-2 overexpressing cells, in basal condition and after store depletion with TG (1 μM) and ionomycin (1 μM). Data are mean ± SEM (n = 5) from two independent experiments in each condition.