Golgi apparatus are primarily responsible for the proper sorting of lipids and proteins in cells.
Consequently, most of the cell-permeant probes for these organelles are either lipids or chemicals that affect protein movement. Several of the most effective probes for the Golgi apparatus are ceramides and sphingolipids, which are also discussed in Section 13.3 . Aspects of lipid trafficking through these organelles that relate to signal transduction are described in Section 18.4 . Several enzymes in the Golgi glycosylate lipids and proteins, resulting in some fluorescent lectins being useful markers for this organelle. In both live and fixed cells, the flattened membranous sacs of the ER and the Golgi apparatus can be stained with a variety of lipophilic probes and then distinguished on the basis of their morphology.