Figure 6.

Bcl-2 increases the permeability of ER-type Ca²⁺ stores. TG (100 nM) was added at time 0 min, and ionomycin (iono; 10 μM) was added either concomitantly with TG, or at later time points (1 min, 2 min, 3 min, 4, min, 5 min). (A and B) Typical experiments showing [Ca²⁺]_c elevations in control and Bcl-2-transfected cells, respectively; four traces with ionomycin addition at different time points are superimposed to facilitate comparison. (C) Ionomycin-releasable Ca²⁺ (expressed as % of the initial peak [Ca²⁺]_c) is plotted as a function of time after TG addition. (D) Time constant (τ) of Ca²⁺ store depletion, calculated for control and Bcl-2-transfected cells by fitting a mono-exponential decay function to the data of C. Results shown in C and D are mean ± SEM of four independent experiments.