Human L-selectin preferentially binds synthetic glycosulfopeptides modeled after endoglycan and containing tyrosine sulfate residues and sialyl Lewis x in core 2 O-glycans.
Endoglycan is a mucin-like glycoprotein expressed by endothelial cells and some leukocytes and is recognized by L-selectin, a C-type lectin important in leukocyte trafficking and extravasation during inflammation. Here, we show that recombinant L-selectin and human T lymphocytes expressing L-selectin bind to synthetic glycosulfopeptides (GSPs). These synthetic glycosulfopeptides contain 37 amino acid residues modeled after the N-terminus of human endoglycan and contain one or two tyrosine sulfates (TyrSO(3)) along with a nearby core-2-based Thr-linked O-glycan with sialyl Lewis x (C2-SLe(x)). TyrSO(3) at position Y118 was more critical for binding than at Y97. C2-SLe(x) at T124 was required for L-selectin recognition. Interestingly, under similar conditions, neither L-selectin nor T lymphocytes showed appreciable binding to the sulfated carbohydrate epitope 6-sulfo-SLe(x). P-selectin also bound to endoglycan-based GSPs but with lower affinity than toward GSPs modeled after PSGL-1, the physiological ligand for P- and L-selectin that is expressed on leukocytes. These results demonstrate that TyrSO(3) residues in association with a C2-SLe(x) moiety within endoglycan and PSGL-1 are preferentially recognized by L-selectin.
Leppänen
Anne
A
Department of Biological Sciences, Division of Biochemistry, University of Helsinki, Helsinki, Finland. Anne.Leppanen@helsinki.fi
Parviainen
Ville
V
Ahola-Iivarinen
Elina
E
Kalkkinen
Nisse
N
Cummings
Richard D
RD
D000595:Amino Acid Sequence; D019921:Biotinylation / Q000502:physiology; D002240:Carbohydrate Sequence; D020134:Catalytic Domain; D006023:Glycoproteins / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D019041:L-Selectin / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009077:Mucins / Q000737:chemistry*; D009844:Oligosaccharides / Q000737:chemistry* / Q000378:metabolism; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism; D000080506:Sialyl Lewis X Antigen; D013379:Substrate Specificity; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
D006023:Glycoproteins; D008562:Membrane Glycoproteins; D009077:Mucins; D009844:Oligosaccharides; C084882:P-selectin ligand protein; D010446:Peptide Fragments; D011134:Polysaccharides; D000080506:Sialyl Lewis X Antigen; C406902:endoglycan; D019041:L-Selectin; C005662:tyrosine O-sulfate; D014443:Tyrosine