Leukosialin, a major O-glycan-containing sialoglycoprotein defining leukocyte differentiation and malignancy.
Leukosialin, also called CD43 or sialophorin, is a major sialoglycoprotein expressed widely in various leukocytes (granulocytes, monocytes/macrophages and T-lymphocytes). Leukosialin is heavily glycosylated by O-linked oligosaccharides (70-80 oligosaccharides/molecule) and the structures of those O-glycans are characteristic to each cell lineage and differentiation stage. In particular, the branched hexasaccharide, NeuNAc alpha 2----3Gal beta 1----3(NeuNAc alpha 2----3Gal beta 1----4GlcNAc beta 1----6)GalNAc is specifically expressed in activated T-lymphocytes as well as in thymocytes and T-lymphocytes from patients with leukaemia, and immuno-deficiency syndromes. A portion of these O-glycans are attached to a domain with tandem repeats in the polypeptide of leukosialin. However, the entire translation product, including such tandem repeats, is coded by one exon and a short novel promoter sequence confers the expression of the leukosialin gene. Leukosialin is apparently involved in T-cell-B-cell interaction during immune reaction and binds to ligands on antigen-presenting B-cells. These results imply that leukosialin plays critical roles in immune cell interaction and differences in attached O-glycans most likely influence the interaction of leukosialin with ligands.
Fukuda
M
M
La Jolla Cancer Research Foundation, Cancer Research Center, CA 92037.
D015703:Antigens, CD / Q000502:physiology*; D002454:Cell Differentiation; D002471:Cell Transformation, Neoplastic; D006021:Glycophorins / Q000235:genetics; D006801:Humans; D007962:Leukocytes / Q000502:physiology*; D051917:Leukosialin; D012795:Sialoglycoproteins / Q000502:physiology*
D015703:Antigens, CD; D006021:Glycophorins; D051917:Leukosialin; C465014:SPN protein, human; D012795:Sialoglycoproteins