Figure 4.

Association of clathrin with endosomal cisternae and the Golgi complex. Cryosections were labeled with anti-clathrin antibodies and PAG-6. Clathrin-mediated budding (A and B, arrows) is frequently observed at the rims of the EC, but sometimes also on planar regions (see arrow pointing at a bent cisterna in C). The pinched-off vesicles (A–C, E, and F, arrowheads) are smaller than CCVs derived from the flagellar pocket membrane (cf. D and Figure 3, B, C, and E). The EXCs (D) are not labeled. Although most Golgi profiles (see G in B) are not labeled, in some images a clathrin coat is present at the ends of (E, arrow) or along the external face of the outermost trans-Golgi cisterna (F, arrows). BZ, budding zone between ER and cis-Golgi; FL, flagellum; K, kinetoplast. Bars (A–F), 250 nm.