Leukosialin, a major sialoglycoprotein defining leucocyte differentiation.
We have isolated a major sialoglycoprotein on leucocytes and found that this glycoprotein, termed leukosialin, is ubiquitously present on various human leucocytes (granulocytes, monocytes/macrophages and T lymphocytes). Our studies showed that leukosialin is significantly glycosylated by O-linked oligosaccharides (70 chains/molecule). The polypeptide portions of these molecules are, however, apparently the same, with a molecular mass of 38.5 kDa. The amino acid sequence derived from cDNA shows tandemly repeated O-glycan attachment sequences, and about 70% of the serine or threonine residues in the external domain are modified by O-glycans. The structures of those O-linked oligosaccharides are characteristic of each cell lineage and maturation stage. In particular, we have shown that O-glycans of leukosialin are converted from NeuAc(alpha 2-3)Gal(beta 1-3) [NeuAc(alpha 2-6)]-GalNAc to NeuAc(alpha 2-3)Gal(beta 1-3) [NeuAc(alpha 2-3)Gal(beta 1-4)GlcNAc(beta 1-6)] GalNAc during T cell activation.
Fukuda
M
M
La Jolla Cancer Research Foundation, Cancer Research Center, CA 92037.
D000595:Amino Acid Sequence; D015703:Antigens, CD; D001483:Base Sequence; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002454:Cell Differentiation; D006801:Humans; D007962:Leukocytes / Q000166:cytology*; D051917:Leukosialin; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000302:isolation & purification; D012795:Sialoglycoproteins / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*
D015703:Antigens, CD; D051917:Leukosialin; D009844:Oligosaccharides; C465014:SPN protein, human; D012795:Sialoglycoproteins