Figure 3. Biosynthetic routes for N-glycan core modifications in nematodes and insects.

Although similar, the routes to core modification of N-glycans in nematodes and insects are subtly different, due to the different specificity of the core α1,3-fucosyltransferase and the presence of the GalFuc epitope; the pathways shown begin with the ‘processed’ form of Man5, which results from the action of ER glucosidases and ER/Golgi class I mannosidases after transfer to protein. The specificities of the enzymes involved have been defined in a number of studies; both descriptive and official protein names are used. Monosaccharides are depicted according to the nomenclature of the Consortium for Functional Glycomics (see Figure 1).