Fig. 8

ER (yellow) export sites with COPII buds and vesicles and associated cis- and medial Golgi cisternae. a Tomographic slice image illustrating a budding and a detached ~ 70 nm in diameter COPII vesicle sandwiched between an ER export site and the cis-side of a Golgi stack. b Tomographic slice image of an ER export site with a COPII vesicle bud, and a cis-Golgi cisterna displaying a ~ 45 nm in diameter COPIa vesicle bud. c–h Tomographic reconstructions illustrating the 3D architecture of an ER export site with budding and free COPII-type vesicles together with the C1 (orange), C2 (green), C3 (blue) cisternae, and remaining cisternae (purple) of a Golgi stack. Note that the ER region shown possesses two COPII vesicle-producing sites separated by a short tubular ER domain with the one on the right (c) producing COPII buds and the one on the left (d) exhibiting 4 COPII vesicles sandwiched between the ER cisternae and adjacent C1 and C2 cis cisternae (e, h). Bars 0.1 µm