P-selectin and E-selectin. Distinct but overlapping leukocyte ligand specificities.
P-selectin on platelets and endothelial cells and E-selectin on endothelial cells are leukocyte receptors that recognize lineage-specific carbohydrates on neutrophils and monocytes. The proposed ligands for these receptors contain the Le(x) core and sialic acid. Since other investigators have shown that both E-selectin and P-selectin bind to sialylated Le(x), we evaluated whether E-selectin and P-selectin recognize the same counter-receptor on leukocytes. The interaction of HL60 cells with Chinese hamster ovary (CHO) cells expressing P-selectin or E-selectin was studied. To determine whether a protein component is required in addition to sialyl Le(x) for either P-selectin or E-selectin recognition, HL60 cells or neutrophils were digested with proteases, including chymotrypsin, elastase, proteinase Glu-C, ficin, papain, or thermolysin. Cells treated with these proteases bound E-selectin but not P-selectin. Fucosidase or neuraminidase treatment of HL60 cells markedly decreased binding to both E-selectin- and P-selectin-expressing CHO cells. Growth of HL60 cells in tunicamycin inhibited the ability of these cells to support P-selectin-mediated binding and, to a lesser extent, E-selectin-mediated binding. Purified P-selectin inhibited CHO:P-selectin binding to HL60 cells, but incompletely inhibited CHO:E-selectin binding to HL60 cells. However, purified soluble E-selectin inhibited CHO:P-selectin and CHO:E-selectin binding to HL60 cells equivalently and completely. COS cells, unable to bind to E-selectin or P-selectin, bound E-selectin but not P-selectin upon transfection with alpha-1,3-fucosyltransferase or alpha-1,3/1,4-fucosyltransferase. Similarly, LEC 11 cells expressing sialyl Le(x) bound E-selectin- but not P-selectin-expressing CHO cells. Sambucus nigra lectin, specific for the sialyl-2,6 beta Gal/GalNAc linkage, inhibited P-selectin but not E-selectin binding to HL60 cells. Although sialic acid and Le(x) are components of the P-selectin ligand and the E-selectin ligand, these results indicate that the ligands are related, having overlapping specificities, but are structurally distinct. A protein component containing sialyl Le(x) in proximity to sialyl-2,6 beta Gal structures on the P-selectin ligand may contribute to its specificity for P-selectin.
Larsen
G R
GR
Genetics Institute Inc., Cambridge, Massachusetts 02140.
Sako
D
D
Ahern
T J
TJ
Shaffer
M
M
Erban
J
J
Sajer
S A
SA
Gibson
R M
RM
Wagner
D D
DD
Furie
B C
BC
Furie
B
B
D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D002240:Carbohydrate Sequence; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D006224:Cricetinae; D004247:DNA / Q000235:genetics; D019040:E-Selectin; D006801:Humans; D007962:Leukocytes / Q000378:metabolism*; D016256:Lewis X Antigen / Q000378:metabolism; D008024:Ligands; D008969:Molecular Sequence Data; D019007:P-Selectin; D010980:Platelet Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism; D013379:Substrate Specificity; D014162:Transfection; D014415:Tunicamycin / Q000494:pharmacology
D015815:Cell Adhesion Molecules; D019040:E-Selectin; D016256:Lewis X Antigen; D008024:Ligands; D019007:P-Selectin; D010980:Platelet Membrane Glycoproteins; D012794:Sialic Acids; D014415:Tunicamycin; D004247:DNA