Extended Data Figure 8: Effect of UV exposure on membrane potential without MitoPhotoDNP.

a, Representative heat map image of an isolated mouse soleus muscle fibre loaded with 5 nM TMRM. N, nucleus; V, vessel. b, c, Image from a thresholded to include only the TMRM signal in the mitochondria (b) or cytosol+nuclei (c). d–f, Whole cell (d), mitochondrial (e) and cytosolic+nuclear (f) TMRM signals immediately after UV exposure in the centre region of the cell (outlined by the white dotted lines). g–i, Post/pre ratiometric whole-cell (g), mitochondrial (h), and cytosolic+nuclear (i) TMRM images showing little change outside of the UV-exposed area. j, Greyscale image of a highlighting the different cell regions used for quantitative analysis. All pixels were analysed. k, TMRM signal decreased in both the mitochondria and cytosol in the UV-exposed region indicative of slight photobleaching. Images are representative of 10 fibres from 3 mice. Data represent the mean ± s.e. from 10 experiments from 3 animals. Asterisk indicates significantly different (ANOVA, P < 0.05) from a post/pre ratio of 1.0. Plus symbol indicates significantly different (P < 0.05) from IFM+UV region. See Supplementary Video 10 for time course video.