Figure 2.

Global mitochondrial Ca²⁺ signals visualized by R-CEPIA3mt and R-CEPIA4mt. (A) Representative images of HeLa cells expressing R-CEPIA3mt (upper) or R-CEPIA4mt (lower). Fluorescence of R-CEPIAs (left), MitoTracker Green staining (middle) and the merged images (right) are shown. Scale bars, 5 µm. (B) Time course of agonist-induced Ca²⁺ response in the mitochondria (upper) and cytosol (lower) in three representative HeLa cells expressing R-CEPIA3mt (left) or R-CEPIA4mt (right). Cytosolic Ca²⁺ signals were visualized by a green fluorescent synthetic Ca²⁺ indicator, Cal-520. (C) Heat maps of cell population data (n = 14) of global Ca²⁺ signals in mitochondria (upper) and cytosol (lower). Each horizontal strip corresponds to the time course of the Ca²⁺ signal in each cell.