DEMONSTRATION OF DIRECT GLYCOSYLATION OF NONDEGRADABLE GLUCOSYLCERAMIDE ANALOGS IN CULTURED-CELLS

After uptake by various cells (human skin fibroblasts, rat neuroblasto ma B 104, human neuroblastoma SHSY5Y, murine cerebellar cells), a radi oactive and a fluorescent analog of a nondegradable glucosylceramide w ith sulfur in the glycosidic link were glycosylated to a cell-specific pattern of glycolipid analogs, These results, for the first time, sho w that a glucosylceramide analog can be conveyed from the plasma membr ane of cultured cells to those Golgi compartments that function in the early glycosylation steps of glycolipids, This observation is further confirmed by the fact that the cationic ionophore monensin, known to impede membrane flow from proximal to distal Golgi cisternae, inhibite d the formation of complex ganglioside analogs but not those of lactos ylceramide, sialyl lactosylceramide (G(M3)), and disialyl lactosylcera mide (G(D3)).