Figure 2. Inhibition of albumin uptake at 20°C.

A, at 20 °C, when the transition from early endosomes (EE) to late endosomes (LE) is slowed down dramatically, EIPA still inhibited endocytosis. By contrast, H⁺-ATPase inhibition with bafilomycin A₁ (bafilo; 1 μmol l⁻¹) exerted only a minor effect and the weak organic base NH₄Cl (100 μmol l⁻¹) was without effect. n = 6-9 for each value plotted. *P < 0.05 vs. control (con). B, the working model of the different sites where EIPA and bafilomycin A₁ are supposed to interact. C, the dose-response curve for EIPA.