Alpha(1,3)-fucosyltransferase VII-dependent synthesis of P- and E-selectin ligands on cultured T lymphoblasts.
T lymphocytes up-regulate the synthesis of ligands for E- and P-selectin during proliferative responses in vivo and in vitro. Previous studies from our laboratories indicated that the alpha(1,3)-fucosyltransferase FucT-VII regulates the synthesis of E-selectin ligands and sialylated Lewis(x)-related epitopes (sLe(x)-related epitopes) in human T lymphoblasts. The current report shows that production of both P- and E-selectin ligands is FucT-VII dependent, but peak synthesis of each occurs at different levels of fucosyltransferase activity in intact cells. In brief, FucT-VII mRNA levels were higher in cultured T lymphoblasts expressing sLe(x)-related epitopes and both selectin ligands than in cells expressing P-selectin ligands alone. However, synthesis of the epitopes and both selectin ligands required the FucT-VII enzyme in transfected Molt-4 cells. In contrast, neither constitutive nor transfection-enhanced levels of the FucT-IV enzyme generated active P-selectin ligands in these lines. In addition, targeted deletion of the FucT-VII gene in mice markedly inhibited the synthesis of both P- and E-selectin ligands during blast transformation in vitro. Finally, the optimal synthesis of active P-selectin ligands occurred at lower level of FucT-VII activity than required for synthesis of equally active E-selectin ligands in both cultured T lymphoblasts and FucT-VII transfectants. Consequently, the FucT-VII enzyme is essential for the synthesis of both P- and E-selectin ligands by T lymphoblasts, and its activity determines whether P-selectin ligands are expressed alone or in conjunction with E-selectin ligands and sLe(x)-related epitopes on human T cells.
Knibbs
R N
RN
Department of Pathology, University of Michigan, Ann Arbor 48109-0602, USA.
Craig
R A
RA
Mály
P
P
Smith
P L
PL
Wolber
F M
FM
Faulkner
N E
NE
Lowe
J B
JB
Stoolman
L M
LM
D000818:Animals; D002461:Cell Line, Transformed; D017077:Culture Media, Conditioned / Q000494:pharmacology; D016895:Culture Media, Serum-Free; D019040:E-Selectin / Q000096:biosynthesis* / Q000235:genetics; D000939:Epitopes / Q000096:biosynthesis; D005647:Fucosyltransferases / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D006801:Humans; D007983:Lewis Blood Group Antigens / Q000096:biosynthesis; D008024:Ligands; D008213:Lymphocyte Activation; D051379:Mice; D018345:Mice, Knockout; D009844:Oligosaccharides / Q000096:biosynthesis; D019007:P-Selectin / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000276:immunology; D000080506:Sialyl Lewis X Antigen; D013601:T-Lymphocytes / Q000201:enzymology / Q000276:immunology / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured
D017077:Culture Media, Conditioned; D016895:Culture Media, Serum-Free; D019040:E-Selectin; D000939:Epitopes; D007983:Lewis Blood Group Antigens; D008024:Ligands; D009844:Oligosaccharides; D019007:P-Selectin; D012333:RNA, Messenger; D000080506:Sialyl Lewis X Antigen; D005647:Fucosyltransferases; C031692:galactoside 3-fucosyltransferase