FIG. 4.

Uptake of Tfr into MA104 cells treated with drugs that affect clathrin-mediated endocytosis. MA104 cells were mock treated (A and B) or pretreated with chlorpromazine (10 μg/ml) (C and D), NH₄Cl (50 mM) (E and F), dansylcadaverine (0.2 mM) (G and H), or sucrose (0.45 M) (I and J), as detailed in Materials and Methods, and then were incubated with Alexa 594-Tfr. The fluorescent signals of Alexa-Tfr are shown in panels B, D, F, H, and J; panels A, C, E, G, and I show the corresponding phase-contrast images.