Figure 4.

(A and B) Transferrin receptors localize to ARF6 and ARF6(T27N) vesicles. CHO cells (A) or HEK 293 cells (B) expressing ARF6 (A) and ARF6(T27N) (A, inset and B) were fixed and processed for cryoimmunogold labeling. Sections were labeled first with the anti-ARF6 antibody followed by protein A–gold (A, 15 nm; B, 10 nm) and then with the anti–Tfn-R antibody followed by protein A–gold (A, 10 nm; B, 5 nm). ARF6 and Tfn-R labeling is seen on the same vesicle (arrows) or on vesicles in near proximity of each other. Arrowhead indicates a clathrin-coated pit. c, centriole; p, plasma membrane. Bar, 200 nm.