Fig. 5

Biotinylation of cell surface proteins reflects the localization of GRP78 and GEP under thapsigargin/tunicamycin treatments in (a) Hep3B and (b) HepG2. Sortilin serves as positive control for cell surface localization; while ERK1/2 and β-actin are negative controls. 1, before loading to avidin column; 2, flow through from the column; 3, wash from the column; 4, elution of the biotinylated cell surface proteins. Starting materials is 1.5 mg/ml. Loading volume of 1 & 2 are 10 μl. Loading volume of 3 & 4 are 20 μl. Tg, 300 nM thapsigargin; Tu, 1.5 μg/ml tunicamycin. Representative blots from three independent experiments are shown