Abstract
N-glycosylation is the most conserved form of protein glycosylation in eukaryotes, but the modifications of N-linked oligosaccharides in plants and invertebrates often differ greatly from those in vertebrates and sometimes result in immunogenic structures. By contrast, O-linked glycans tend to be a wide and disparate group of modifications. Whereas the forms of O-linked glycans in plants are unlike those in animals, studies on invertebrate O-glycosylation often yield information relevant to mammalian systems.