Modification of CD43 and other lymphocyte O-glycoproteins by core 2 N-acetylglucosaminyltransferase.
CD43, the major leukocyte sialoglycoprotein, is expressed on T lymphocytes in two predominant glycoforms. CD43 115 kDa is a pan T cell marker and is specifically recognized by the monoclonal antibody S7. CD43 130 kDa is associated with T cell activation and is specifically recognized by the monoclonal antibody 1B11. The thymoma EL-4 has been identified to express mainly CD43 115 kDa and little or no CD43 130 kDa. Transfection of EL-4 cells with core 2 beta 1-->6N-acetylglucosaminyltransferase (C2GnT), an enzyme in the O-glycan biosynthesis pathway, resulted in an enhanced expression of the 1B11 epitope, CD43 130 kDa, and a loss of expression of the S7 epitope, CD43 115 kDa. Analysis of CD43 by SDS-PAGE revealed that CD43 in C2GnT transfected EL-4 cells has a molecular weight of 125 kDa compared to 115 kDa in nontransfected or control transfected EL-4 cells. SDS-PAGE analysis of three other lymphocyte O-glycoproteins, CD44, CD45, and RPTP alpha, revealed that C2GnT expression resulted in a molecular weight increase of approximately 3-5 kDa for each of these three cell surface glycoproteins. Our data indicate that, while CD43 may be a predominant substrate for C2GnT, other lymphocyte O-glycoproteins are also modified by this glycosyltransferase. Increased reactivity of cells with the monoclonal antibody 1B11, which specifically detects the expression of murine CD43 130 kDa, may thus be a marker of increases in branching of O-linked glycans generally.
Barran
P
P
Biomedical Research Centre, University of British Columbia, Vancouver, Canada.
Fellinger
W
W
Warren
C E
CE
Dennis
J W
JW
Ziltener
H J
HJ
D000818:Animals; D015703:Antigens, CD; D018960:Hyaluronan Receptors / Q000235:genetics; D017493:Leukocyte Common Antigens / Q000235:genetics; D051917:Leukosialin; D051379:Mice; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics / Q000378:metabolism*; D017027:Protein Tyrosine Phosphatases / Q000235:genetics; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4; D011956:Receptors, Cell Surface; D012190:Retroviridae / Q000235:genetics; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D018960:Hyaluronan Receptors; D051917:Leukosialin; D011956:Receptors, Cell Surface; D012795:Sialoglycoproteins; C497863:Spn protein, mouse; D017351:N-Acetylglucosaminyltransferases; C037649:N-acetyllactosaminide beta-1,6-N-acetylglucosaminyltransferase; D017493:Leukocyte Common Antigens; D017027:Protein Tyrosine Phosphatases; C516843:Ptpra protein, mouse; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4