Fig. 6

MCU redistributes with MICU1 correlative to intermembrane Ca²⁺ spikes. a HeLa cells were transiently transfected with MCU-mCherry and MICU1-YFP and imaged with SIM under resting conditions (−Hist) and 90 s after stimulation with histamine (100 µM) (+Hist). Representative SIM captures showing the distribution of MCU-mCherry (magenta) and MICU1-YFP (green) are presented. Dotted squares indicate areas shown at high magnification in the upper right corner. b Statistical analysis of the sub-mitochondrial MCU-mCherry distribution in MICU1- or ∆C-MICU1-YFP- expressing cells represented as IBM association index (n = 8). Horizontal lines represent the median, the lower and upper hinge show respectively first quartile and third quartile, and lower and upper whisker encompass minimal and maximal values. c Representative images (top and middle) and line plots (bottom) of MCU-mCherry (magenta) and MICU1-YFP (green) under resting conditions (0 s) and 15, 60, 180 and 300 s after stimulation with histamine (100 µM) in nominally Ca²⁺-free buffer. d Time correlation between the accumulation of MCU in the IBM (magenta points) and mitochondrial Ca²⁺ concentration (green line and gray error bars) upon stimulation with 100 µM histamine (n = 9). Cells were transiently transfected with mito-R-GECO1 to measure mitochondrial matrix Ca²⁺ concentrations upon histamine (green line) (n = 8). Data are shown as mean ± SEM as middle line and whiskers, respectively. *P < 0.05 vs. respective control conditions carried out with unpaired double-sided T-test. Source data are provided as a Source Data file