(A) The G544V-mutant LDL receptor fails to reach the Golgi complex (Tveten et al., 2007). CHO cells stably transfected with wild-type (lane 1) or mutant LDL receptor were induced with tetracycline for 24 hr at 37°C before further incubation for 2 hr at 37°C (lane 2) or 30°C (lane 3), or 2 hr incubation at 37°C with 10 mM 4-PBA (lane 4). Cell lysates were analyzed by immunoblotting; labeling indicates the 160 kDa mature glycosylated and 120 kDa precursor forms of LDL receptor. (B) Dose-dependent restoration of trafficking of mutant LDL receptor by 4-PBA (see also Tveten et al., 2007). CHO cells expressing mutant LDL receptor were incubated with indicated concentrations of 4-PBA for 2 hr at 37°C. Cell lysates were analyzed as in (A). (C) The packaging of a series of p24 proteins, ER residents and mutant LDL receptor were assayed in scaled-up COPII budding reactions. Lane labeled Input represents 1.1% of the starting membranes; all other lanes represent the vesicle product of 100% of the starting membranes. Experiments were performed in triplicate. (D) Packaging rates for the p24-family proteins p24δ1 and p24α2, presented as in 2D (controlled by Syntaxin 5, membrin, Erv46 and Rer1 packaging rates). The data for p24α3 and p24β1 are in Figure 2D (n = 3; ANOVA test, Bonferroni-Holm post hoc, *p<0.05, **p<0.01 and ****p<0.0001). Bar graphs show mean ± s.e.m. (E) Graph shows packaging rates for four ER resident proteins and mutant LDL receptor. Note the change of scale of the y-axis (n = 3; ANOVA test, Bonferroni-Holm post hoc, *p<0.05, **p<0.01 and ***p<0.001). Bar graphs show mean ± s.e.m.