Mitochondrial temperature fluctuates in response to substrate availability
(A, C, D, E) Representative fluorescence ratio traces of mito-gTEMP expressing iMEF(P) cells resuspended in various media without OXPHOS inhibitors. PBS – phosphate-buffered saline, glc – glucose and gln – glutamine at standard cell-culture concentrations, BKA – bongkrekic acid. Arrows indicate time of addition of substrates or of BKA. Mitochondrial temperatures (°C) extrapolated from calibration curve (Fig. 3D) shown in red boxes. (B) Mitochondrial temperatures (°C, means + SD of 5 independent experiments), averaged over the time intervals since cell resuspension as shown, extrapolated from mito-gTEMP fluorescence ratios using calibration curve (Fig. 3D), for cells with and without substrate additions as shown. *, **, *** denote statistical significance (p < 0.05, 0.01, 0.001, respectively, one-way ANOVA with Tukey post-hoc HSD test). (F) Mitochondrial temperatures (°C, means + SD, n = 3 independent experiments), averaged over the time intervals since cell resuspension as shown, extrapolated from mito-gTEMP fluorescence ratios using calibration curve (Fig. 3D), for cells treated with BKA at 11 min (values averaged over 11-16 min) and then tracked until 35 min (final values averaged over 30-35 min). *, **, *** denote statistical significance (p < 0.05, 0.01, 0.001, respectively, one-way ANOVA with Tukey post-hoc HSD test).