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

The first system was VSV-infected cells that have been left at 20°C for 2 h. Under this condition, the bulk of the G protein accumulates predominantly in the TGN, which enlarges considerably while the Golgi stack shrinks (Griffiths et al., 1985 (Griffiths et al., , 1989 . In addition to the TGN, significant amounts of G protein may also accumulate throughout the Golgi stack. Here, we used mouse L ceils that were infected with a ts045 strain of VSV at 37 ° for 1 h, switched to 39 ° to accumulate the G protein in pre-Golgi structures, and then put at 20°C for 2 h in the presence of cycloheximide (Grifliths et al., 1985) . When sections of these preparations were doublelabeled for the G protein (using antibodies against either the lumenal or cytoplasmic domains) and the KDEL-R, there was extensive colocalization of both markers (Fig. 9) . In many parts of these cells, the distinctive features of the TGN could be easily recognized, and some of these regions had relatively high levels of labeling for the KDEL-R (Fig. 9) .