Figure 2. MCU silencing strongly inhibits mitochondrial Ca²⁺ uptake without causing morphological rearrangement or changes in the electrochemical gradient.

a, [Ca²⁺]_mt and b, [Ca²⁺]_cyt measurements in MCU-silenced cells. c, Fluorescence images of mtRFP- and erGFP-labeled mitochondria and ER, respectively. d and e, Mitochondrial number and volume, as deduced by calculating object number (d) and size (e). f, ER/mitochondria colocalization, estimated by Pearson's correlation coefficient. g, TMRM fluorescence measurements. h, [Ca²⁺]_mt measurements in permeabilized cells. In this and following figures, experiments are representative of >5 trials, conditions are in the methods section, and statistics in Supplementary Table 2. * p<0.05, ** p<0.001