Abstract
Caenorhabditis elegans makes about 150 individual N-glycan structures. This review discusses the synthesis and possible functions of the paucimannose N-glycans that are highly abundant in invertebrates but not in vertebrates. The complexity of the worm's N-glycans is due in part to a variety of unusual fucosylation reactions and the addition of phosphorylcholine. Phosphorylcholine has been recognized as a widespread antigenic determinant in many important disease-causing parasites. The synthesis of paucimannose N-glycans depends on the prior action of UDP-GlcNAc:α3-D-mannoside β1,2-N-acetylglucosaminyltransferase I (GnTI, encoded by Mgat1). There are three GnTI isoenzymes in the worm (GLY-12, GLY-13, GLY-14). Each GnTI isoenzyme has a distinct set of target proteins and a distinct role in the interaction of C.elegans with pathogenic bacteria. Identification of the protein substrates of GnTI in worms and elucidation of their functions may lead to a better understanding of the role of GnTI-dependent glycoproteins in the survival of both invertebrates and vertebrates.
