Many proteins of higher organisms are glycosylated, that is, they have short chains of sugar derivatives added after translation. Glycosylation is required for proper biological function of many proteins.
One advantage of expressing proteins in insect cells is that they do possess a glycosylation pathway. The pathway for posttranslational glycosylation of asparagine residues is shared by mammals and insects up to the addition of mannose (Fig. 10.12). However, the pathways diverge beyond this. Nonetheless, partial glycosylation is better than none. Furthermore, insect cell lines that have been engineered to express the full mammalian glycosylation pathway are now available.