D-E. Mitochondrial H2O2 levels are critically blunted after MCU depletion. Cells were transfected with shMCU or shControl, together with the ratiometric YFP-based biosensor pHyper-dMito (D) or the mitochondrial H2O2-sensitive HyPerRed probe (E). 48 hours later, H2O2 production was measured (n=35). P-values: *p=0.02, *p=0.05, respectively. 