FIG. 1.

Effects on HdCDT-induced intoxication of drugs which inhibit endosomal acidification. Cells were preincubated with methylamine (10 mM), NH₄Cl (20 mM), or monensin (10 μM), treated with the toxin for 15 min, and postincubated for 12 h in the presence of the respective drug. Tyrosine phosphorylation of cdc2 in the treated cells was determined by Western blotting as described in Materials and Methods. Blots are representative of two different experiments with each drug.