Expression of PPX does not alter mitochondrial Ca²⁺ handling during moderate elevation of [Ca²⁺]_em. (A) Original recordings of [Ca²⁺]_m changes in permeabilized myocytes upon elevation of [Ca²⁺]_em from 0.1 to 0.8 µM, and subsequent return to 0.1 µM in control and PPX-infected cells. (B) Average values of mitochondrial Ca²⁺ uptake (left) and extrusion (right) ([Ca²⁺]_m amplitudes measured at 5 min of Ca²⁺ addition or removal) in control and PPX-expressing cells.