Human L-selectin preferentially binds synthetic glycosulfopeptides modeled after endoglycan and containing tyrosine sulfate residues and sialyl Lewis x in core 2 O-glycans

• Published in: Glycobiology (Oxford) 2010-09, Vol.20 (9), p.1170-1185
• Main Authors: Leppänen, Anne, Parviainen, Ville, Ahola-Iivarinen, Elina, Kalkkinen, Nisse, Cummings, Richard D
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Biotinylation - physiology; Carbohydrate Sequence; Catalytic Domain; endoglycan; Glycoproteins - chemical synthesis; Glycoproteins - chemistry; Glycoproteins - metabolism; glycosulfopeptide; Glycosylation; Humans; L-selectin; L-Selectin - metabolism; Membrane Glycoproteins - chemistry; Membrane Glycoproteins - metabolism; Models, Molecular; Molecular Sequence Data; Mucins - chemistry; O-glycan; Oligosaccharides - chemistry; Oligosaccharides - metabolism; Original; Peptide Fragments - chemical synthesis; Peptide Fragments - chemistry; Peptide Fragments - metabolism; Polysaccharides - chemistry; Polysaccharides - metabolism; Substrate Specificity; Tyrosine - analogs & derivatives; Tyrosine - chemistry; Tyrosine - metabolism; tyrosine sulfate
• ISSN: 0959-6658; 1460-2423
• DOI: 10.1093/glycob/cwq083

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 (TyrSO3) along with a nearby core-2-based Thr-linked O-glycan with sialyl Lewis x (C2-SLex). TyrSO3 at position Y118 was more critical for binding than at Y97. C2-SLex 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-SLex. 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 TyrSO3 residues in association with a C2-SLex moiety within endoglycan and PSGL-1 are preferentially recognized by L-selectin.