Fig. 9. Intracellular Ca²⁺ chelation partially reverses the effect of PDMP on ER architecture. Induced HeLa TetOff cells were treated with 100 µM PDMP for 3 hours. During the last hour of incubation the medium was supplemented with 50 µM BAPTA-AM (right panel) or vector (left panel). After fixation, the cells were analysed by confocal microscopy. The percentage of cells showing SER patches was determined on eight randomly selected fields, such as those illustrated in the figure. The difference between the percentages of responding cells under the two conditions (indicated under the panels ± s.e.m.) was highly significant by Student's t-test (P=1.7x10^-5).