Glycosylation in S2 cells is very similar to that of SF9, Sf21, and High Five cells. The nature of Drosophila N-linked glycosylation is less complex than mammalian glycosylation – it is generally of the paucimannose type and is not trimmed and sialylated.
O-linked glycosylation is similar, although not identical, to that obtained in mammalian cells. However, human glycosylation profiles are difficult to obtain, also glycosylation from CHO and HEK293 differ from human glycosylation. Human O-glycosylation can be divided into N-acetylGalactosamine linked (mucin type), N-acetylGlucosamine lined (O-GlcNAc type) and xylose linked (proteoglycans) families. The most abundant form is the mucin type, while O-GlcNac has only been found for cytoplasmic and nuclear proteins, the proteoglycans are of less interest here.
In CHO cells, O-glycosylation results in terminally sialated mucin type glycans, with a low percentage core-1 structure (T-antigen) reported. In Drosophila S2, cell O-glycosylation is less complex than in human or mammalian cells. Unlike human proteins, O-GlcNAc has been found on an external protein. It appears that O-GlcNAc can occur in specific cases and are linked to the regulation of the protein, in this case the Notch receptor. However, mucin type glycosylation is the dominant O-glycosylation type in S2 cells and has been shown to be of the Tn-antigen (GalNAcalpha-Ser/Thr) and the core-1 structure (T-antigen) (Galbeta1-3GalNAcalpha-Ser/Thr) forms.
More information on glycosylation insert can be found here.
More information on S2 cells and glyco-engineered S2 cell lines can be found here.