FIGURE 6.

Characterization of mitochondrial pH and the effect of pH on the sensor. A, mito-Cys₂His₂ sensor FRET ratio as a function of pH. B, measurement of mitochondrial pH at rest and upon treatment with 100 μm glutamate stimulation (Glu). C, measurement of mitochondrial pH at rest and upon treatment with 100 μm glutamate, 250 μm Zn²⁺. For B and C, the pH calibration was performed immediately following stimulation using the same region of interest from three individual cells as described in the supplemental text.