Fig. 1.

Mitochondrial cAMP level is lower in cystinotic cells and increased by cysteamine treatment. ciPTEC obtained from a healthy volunteer (CTNS^+/+) and from two cystinotic patients (delCTNS^−/− or mutCTNS^−/−) were transfected (transiently) with the EPAC-based FRET sensor target specifically to mitochondria (4mtH30) (a) or cytosol (H96) (b). Where indicated, the cells were treated with 100 µM cysteamine (MEA) or DMSO (vehicle) for 24 h. The histograms represent the means values ± SEM of net% FRET observed (ANOVA test). For other details, see under “Methods” section