Figure 4: RT-based imaging and quantification of glutathione in living cells.

(a) Confocal and ratiometric images of HeLa cells stained with RT (refer to Supplementary Fig. 4 for details on generating ratiometric images). Scale bar, 20 μm. (b) Quantitative analysis of GSH level fluctuations in HeLa cells on consecutive treatment with H₂O₂ (500 μM) and GSH ester (100 μM). Each data point represents the mean value of 46 cells analysed from one representative time-lapsed imaging experiment. Error bars represent s.e.m. (c) Representative images of dynamic changes of GSH levels in HeLa cells on consecutive treatments with H₂O₂ and GSH ester. Scale bar, 20 μm. (d) Lysate-based GSH levels measured using LCMS. HeLa cells were treated with H₂O₂ only (orange), H₂O₂ followed by GSH ester (moss), GSH ester only (turquoise) or PBS (pink). The cells were lysed and the amounts of GSH were quantified using LCMS. Each data point represents the mean value of two independent experiments. Error bars represent s.d.