The fucosyltransferase FucT-VII regulates E-selectin ligand synthesis in human T cells.
Selectin-ligands on T cells contribute to the recruitment of circulating cells into chronic inflammatory lesions in the skin and elsewhere. This report provides the first evidence that a single fucosyltransferase, termed FucT-VII, controls the synthesis of E-selectin ligands in human T-lymphoblasts. The FucT-IV transferase (the ELFT enzyme), in contrast constructs lower avidity E-selectin ligands and requires enzyme levels found only in myeloid cells. Treatment of Jurkat cells with phorbol myristate acetate increased the expression of sialylated Lewis(x)-related sLe(x)related epitopes and induced the synthesis of E-selectin ligands functional at physiologic levels of linear shear-stress. Northern analysis revealed a parallel increase in the steady-state levels FucT-VII mRNA, but there were no increases in the two other leukocyte-associated fucosyltransferases (FucT-IV and VI). The stable transfection of the FucT-VII gene into Jurkat cells induced high levels of the sLe(x)-related epitopes and the synthesis of E-selectin ligands which equal or exceeded the avidity of those on circulating lymphocytes. The growth of T-lymphoblasts under conditions which induced expression of the sLe(x,a) epitopes increased the level of FucT-VII mRNA, the synthesis of sialylated-Lewis(x) structures by cell-free extracts and the synthesis of E-selectin ligands equal in avidity to those on FucT-VII transfectants. In contrast, neither the mRNA levels nor activities of the FucT-IV and VI enzymes increased in association with E-selectin ligand synthesis in T-lymphoblasts. Myeloid cell lines, unlike lymphoblasts, expressed high levels of both the FucT-VII and IV enzymes in conjunction with E-selectin ligands raising the possibility that both enzymes contributed to ligand synthesis. FucT-IV transfected Jurkat cells synthesized low avidity ligands for E-selectin but only in association with CDw65 (VIM-2) carbohydrate epitope. Only blood neutrophils and myeloid cell lines expressed this epitope at the levels associated with E-ligand synthesis in the transfectants. In contrast, native Jurkat cells, blood monocytes, blood lymphocytes, and cultured T-lymphoblasts expressed low levels or none. We conclude that FucT-VII is a principal regulator of E-selectin ligand synthesis in human T-lymphoblasts while both FucT-VII and FucT-IV may direct ligand synthesis in some myeloid cells.
Knibbs
R N
RN
Department of Pathology, University of Michigan, Ann Arbor 48109-0602, USA.
Craig
R A
RA
Natsuka
S
S
Chang
A
A
Cameron
M
M
Lowe
J B
JB
Stoolman
L M
LM
D015703:Antigens, CD; D015704:CD4 Antigens / Q000276:immunology; D016827:CD8 Antigens / Q000276:immunology; D019040:E-Selectin / Q000378:metabolism*; D005647:Fucosyltransferases / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008024:Ligands; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D009844:Oligosaccharides / Q000378:metabolism; D000080506:Sialyl Lewis X Antigen; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D015704:CD4 Antigens; D016827:CD8 Antigens; C096764:CDw65 antigen, human; D019040:E-Selectin; D008024:Ligands; D008562:Membrane Glycoproteins; D009844:Oligosaccharides; D000080506:Sialyl Lewis X Antigen; D005647:Fucosyltransferases; D013755:Tetradecanoylphorbol Acetate