Alpha (1,2) Fucosylated Glycoepitopes from Invertebrates to Humans

Glycans participate in bio-communication, such as cell to cell recognition, sperm-egg recognition and embryonic development because they have the property of storing biological signals in forms that can be identified by other biological systems, such as anti-glycan antibodies and glycan binding proteins or lectins. Aberrant arise at the cell surface in many diseases, including cancer, and altered carbohydrate moieties are indicated as mediators of tumorigenicity and invasiveness. Alpha-L-fucopyranosyl residues are immunodeterminant, playing an important role in the glyco-language; this is especially true of residues alpha(1,2)-linked to a galactose, that frequently exist as terminal modifications of N-glycans, O-glycans or glycolipids. The H antigen is the product of the enzyme that adds fucose to galactose residues by an alpha(1,2)-linkage. We report work in which we demonstrated the presence and role of alpha(1,2)fucose-containing glycoepitopes in biocommunication between egg and sperm in two invertebrate species, the tunicate Ciona intestinalis and the mollusk Unio elongatulus. In the mollusk the structure of the fucosylated epitopes involved in sperm recognition in the context of the blood group H-antigen was confirmed by MS/MS data. Using an antibody raised against the bio-communicating glycoprotein of the Unio oocyte, the epitope of which was demonstrated to contain the alpha(1,2)fucosylated O-glycans, we detected the same or a very similar epitope in nucleolin, a protein expressed in highly proliferating and cancer cells in humans, known to act as a shuttle between the cell surface and nucleus. We suggest that the glycosylation machinery used to build up the alpha(1,2)fucosyl-containing glycoepitope of the Unio egg, is re-stored in cancer cells.