K-562 cells, which express foetal erythroglycan, are shown to synthesize the lipid-linked oligosaccharide intermediates commonly found in tissues and cultured fibroblasts. The addition of tunicamycin, which blocks the formation of these intermediates and thus of asparagine-linked oligosaccharides, inhibits the synthesis of erythroglycan (Mr 7000-11 000). Vesicular-stomatitis-virus infection of K-562 cells results in the glycosylation of the G-protein with the transferrin-type oligosaccharide (Mr 3000), but not with the larger erythroglycan. These results suggest that, in K-562 cells, the early stages of erythroglycan biosynthesis are the same as those of the transferrin-type oligosaccharides. However, maturation of the oligosaccharide is influenced by protein structure such that erythroglycan is only expressed on specific glycoproteins.
