Fig. 4.

Regulation of Zn²⁺ uptake in ER. (A) Thapsigargin enhanced Zn²⁺ uptake in ER. HeLa cells expressing ER-ZapCY1 sensor were treated with DMSO (n = 17 cells, three experiments) or 100 nM thapsigargin (n = 17 cells, three experiments) for 5 min (R₀), and then incubated with 100 μM ZnCl₂ (R). The relative ratio (R/R₀) indicates the changes of Zn²⁺ in ER. (B) Effect of different drugs on Zn²⁺ uptake in ER. HeLa cells expressing ER-ZapCY1 sensors were treated with DMSO (n = 17 cells from three experiments), 100 nM thapsigargin (n = 17 cells, three experiments), 50 μM 2-APB (n = 23 cells, three experiments), 100 μM histamine (n = 18 cells from three experiments), or 50 μM diltizem (n = 17 cells, three experiments) for 5 min followed by addition of 100 μM ZnCl₂ to activate ER Zn²⁺ uptake for 30 min. Compared with DMSO, thapsigargin, histamine, and diltiazem induced greater Zn²⁺ uptake (**p < 0.01, ANOVA, Tukey honestly significant difference post hoc test).