Localization of the Lys, Asp, Glu, Leu tetrapeptide receptor to the Golgi complex and the intermediate compartment in mammalian cells

We first asked whether rabl colocalized with p58 and with the membranes where MHV bud in L cells infected with this virus and permeabilized with SLO. As shown in Fig. 4 , there was extensive labeling for rabl in all the membrane structures that we had previously identified as having a role in the budding of the virus, including parts of the nuclear envelope (Fig. 4 B) . The labeling for rabl colocalized with p58, but it was much more extensive. There were detectable but significantly lower levels of labeling for both markers over the rough ER (Fig. 4, A and B) . The rabl labeling also extended to one or two cisternae on the cis side of the Golgi stack, which also contained budding virion profiles. Rabl and p58 also colocalized in uninfected L cells treated with SLO, and the amount of labeling for both markers was very similar to the levels seen in infected cells (Fig. 5 A) . Fig. 5 A documents the extensive network of interconnected membrane structures that extend considerable distances away from recognizable Golgi stacks. This network comprises many different morphological structures. The large arrow in Fig. 5 A points to a continuity between an apparently tubular structure with a larger, more electron-dense domain of the IC. Vesicular buds that have the morphological features expected of COP coats are also apparent on the IC (Fig. 5 A) . In Fig. 5 B, the extent of rabl labeling of Golgi associated cisterna(e) is apparent.