Figure 4.

Matrix proteins (GCC88 and GM130) collect into nascent Golgi structures, whereas a glycosyltransferase stays in the ER. HeLa cells stably transfected with GalNAcT2-GFP were double-labeled with GCC88 and GM130 before and after BFA/H89 washout. Each protein was found in a compact juxtanuclear Golgi structure in nontreated cells (A–C). After BFA/H89 washout at 32°C, GCC88 and GM130 displayed similar behavior and accumulated much faster than GalNAcT2 into post-ER punctae (G–L). The juxtanuclear Golgi structure was positive for all after 4 h (M–O). All micrographs were taken with a wide-field Zeiss Axiovert 200M microscope with the camera mounted on the baseport. Arrows in I and L point to examples of nuclear envelope, i.e., ER distribution of GalNAcT2 versus GM130. Bar, 10 μm.