Figure 10.

When present during endocytosis, drugs protecting cells from PE intoxication impaired endosomal ¹²⁵I-labeled PE translocation. The following concentrations were used: NH₄Cl/methylamine (AC/MA), 20 mM each; chloroquine, 50 μM; monensin, 50 μM; nigericin, 5 μM; bafilomycin A1, 0.5 μM; BFA, 5 μg/ml. Effect on translocation: cells were labeled with 1 μg/ml ¹²⁵I-labeled PE (in the absence of drug) before endosome isolation; translocation was assayed in the presence of the indicated molecules (n = 6). Effect during endocytosis, i.e., on acquisition of translocation competence: cells were preincubated for 10 min at 37°C in the presence of the indicated molecules before adding 1 μg/ml ¹²⁵I-labeled PE and 150 μg/ml LDL. After 30 min at 37°C, cells were fractionated to isolate endosomes. Translocation was assayed in the absence of drug (n = 4). ND, not determined.