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. 2020 Oct 17;9(10):2311. doi: 10.3390/cells9102311

Figure 4.

Figure 4

ER-to-Golgi transport of the transmembrane cargo construct in HeLa cells is boosted by glucose starvation but blocked by 2-DG. (a) Classification of glucose-deprived HeLa cells (n = 39 cells from 3 independent experiments) based on the efficiency of ER-to-Golgi transport of GFP-FM4-VSVGtm. Cells were treated with buffer lacking glucose for 30 min prior to transport initiation. Transport was classified as very high (red, transport index at 15 min > 10), high (orange, transport index > 7, <10), moderate (green, transport index > 4, <7), or no transport (blue, transport index < 4); (b) Classification of 2-DG-treated HeLa cells (n = 51 cells from 4 independent experiments) based on ER-to-Golgi transport efficiency. Transport was initiated and measured after pretreating cells with buffer containing 10 mM 2-DG for 30 min before the addition of solubilizer; (c) Comparison of the percentages of tested HeLa cells in the four classes for each pretreatment condition. Cells were treated for 30 min before transport initiation with buffer containing 10 mM glucose (+ Glu, control, n = 58 cells from 4 independent experiments), no glucose (− Glu, n = 39 cells from 3 independent experiments), or 10 mM 2-DG (+ 2-DG, n = 51 cells from 4 independent experiments). # significant versus + Glu p < 0.05, Chi-square test; (d) Transport index comparison of HeLa cells of different pretreatment conditions (+ Glu (grey), n = 58 cells, − Glu (blue), n = 39 cells, + 2-DG (red), n = 51 cells) at the indicated time points after transport initiation. Bars represent mean ± SEM. *** significant versus control (+ Glu) at the same time point p < 0.001, # significant versus all other time points of the same condition p < 0.05, Kruskal–Wallis test and Dunn’s post hoc test; (e) Transport of soluble (Sol., GFP-FM4-GH) and transmembrane construct (TM, GFP-FM4-VSVGtm) normalized to control conditions at indicated time points. Bars represent mean values ± SEM. * significant versus control (+ Glu) at the same condition p < 0.05, *** p < 0.001, Mann–Whitney U test.