Figure 5
From: ZnT2 is a critical mediator of lysosomal-mediated cell death during early mammary gland involution
TNFα redistributes ZnT2 away from the secretory compartment and mitochondria to lysosomes.
Representative confocal images showing ZnT2 (green) colocalized (merge, yellow) with (a) Lamp1 (red, lysosomal marker) in TNFα-treated cells. ZnT2 was not localized to lysosomes in untreated cells. ZnT2 (green) colocalized (merge, yellow) with (b) COX IV (red, mitochondrial marker) in untreated cells. ZnT2 was not localized to mitochondria in TNFα-treated cells. Scale bars = 10 μm. (c) Pearson's correlation coefficient for colocalization of endogenous ZnT2 (green) and Lamp1 or COXIV (red). Data represent mean ± SD of at least 5 fields of view from three independent experiments. **P < 0.001 and ***P < 0.0001. (d)–(e) Protein abundance of ZnT2 in lysosome- and mitochondria-enriched fractions from untreated (Unt) and TNFα-treated cells was determined by immunoblot. Lamp1 was used to verify the presence of lysosomes and β-actin and SDH were used as loading controls. Ratios of signal intensities are reported under the blots. (f) Mitochondrial Zn pools were quantified using RhodZin-3-AM in cells treated with TNFα and compared to untreated cells. Cells with no RhodZin-3-AM (No dye) are included to account for background fluorescence. Values represent mean fluorescence/μg protein ± SD, n = 8/treatment. Experiment was conducted three independent times. **P < 0.001, ***P < 0.0001 and n.s., not significant.
