Figure 3.

Cells expressing the S²⁸⁸ variant of ZnT2 have increased oxidative stress, lysosomal activity and STAT3 activation. (a) Assessment of reactive oxygen species (ROS) level in untransfected MECs (Control) or MECs transfected to express wild-type ZnT2 (T²⁸⁸) or the ZnT2 variant (S²⁸⁸). Cells treated with H₂O₂ (100 µM) were used as a positive control. Data represent mean DCF-HA fluorescence/µg of protein ± SD, from n = 6 samples/group; the experiment was repeated three times. Means with different letters are significantly different, p < 0.01. (b) Representative confocal images of FluoZin-3 (green) and Lysotracker Red (red) in MECs expressing T²⁸⁸ or S²⁸⁸. Merged images (yellow) illustrate co-localized FluoZin-3 and Lysotracker Red. Note greater Lysotracker Red fluorescence in MECs expressing T²⁸⁸ compared with MECs expressing S²⁸⁸ (scale bar, 20 µm). (c) Representative immunoblots of p-STAT3 and total STAT3 in cell lysates from MECs expressing T²⁸⁸, S²⁸⁸, or mock-transfected (Mock) cells. β-actin served as a loading control. Cropped blots are displayed and full-length blots can be found in Supplementary Fig. S4a–c. (d) Quantification of STAT3 activation. Data represent mean p-STAT3/total STAT3 ± SD from n = 6 samples/genotype, from three independent experiments. Means with different letters are significantly different, p < 0.05.