Identification of a specific glycoprotein ligand for P-selectin (CD62) on myeloid cells.

Abstract

Abstract. P-selectin (CD62, GMP-140, PADGEM), a Ca2+-dependent lectin on activated platelets and endothelium, functions as a receptor for myeloid cells by interacting with sialylated, fucosylated lactosaminoglycans. P-selectin binds to a limited number of proteasesensitive sites on myeloid cells, but the protein(s) that carry the glycans recognized by P-selectin are unknown. Blotting of neutrophil or HL-60 cell membrane extracts with [m25I]P-selectin and affinity chromatography of [3H]glucosamine-labeled HL-60 cell extracts were used to identify P-selectin ligands. A major ligand was identified with an =250,000 Mr under nonreducing conditions and =120,000 under reducing conditions. Binding of P-selectin to the ligand was Ca 2 § dependent and was blocked by mAbs to P-selectin. Brief sialidase digestion of the ligand increased its apparent molecular weight; however, prolonged digestion abolished binding of P-selectin. Peptide:N-glycosidase F treatment reduced the apparent molecular weight of the ligand by =3,000 but did not affect P-selectin binding. Western blot and immunodepletion experiments indicated that the ligand was not lamp-I, lamp-2, or L-selectin, which carry sialyl Le ~, nor was it leukosialin, a heavily sialylated glycoprotein of similar molecular weight. The preferential interaction of the ligand with P-selectin suggests that it may play a role in adhesion of myeloid cells to activated platelets and endothelial cells.

Partial characterization of the N-linked oligosaccharide structures on P-selectin glycoprotein ligand-1 (PSGL-1)

“…Whether these putative fucosylated structures are of functional importance for selectin binding remains to be determined. Previous reports have described the N-glycans on PSGL-1 as dispensable for binding [28] and a considerable body of evidence suggest that the selectins bind to Olinked oligosaccharide structures on PSGL-1 [7][8][9][10], [14]. A specific threonine residue has been identified in the NH2-terminal portion of PSGL-1 that is believed to carry the (O-linked) ligand oligosac-charide recognized by P-selectin [29][30][31].…”

“…PSGL-1 is a ligand capable of binding P-, Eand L-selectin [7][8][9][10][11][12][13]. The molecule is expressed on several cell types, including human leukocytes and the human myeloid cell line HL-60 [7], [10], [14].…”

“…The molecule is expressed on several cell types, including human leukocytes and the human myeloid cell line HL-60 [7], [10], [14]. Moreover, successful cloning from an HL-60 cDNA library has revealed that PSGL-1 is a type I membrane glycoprotein with a domain structure similar to that of many cell surface mucins [9], [15].…”

Platelets induce monocyte differentiation in serum-free coculture

“…Different receptors like PSGL-1 or CD15 on MO and activated platelets seem to be involved in MO-platelet interaction [35][36][37][38][39][40][41]. In addition, phosphatidylserine is known to mediate interaction of MO with different cell types [42].…”

SELPLG Gene Polymorphisms in Relation to Plasma SELPLG Levels and Coronary Artery Disease

“…Among the various P-selectin ligands already described (Vestweber & Blanks, 1999), the P-selectin glycoprotein ligand-1 (SELPLG/CD162) seems to be the major one mediating leukocyte recruitment to platelets and the endothelium (Kansas, 1996;Norman et al 1995). SELPLG is a dimeric mucinlike glycoprotein expressed on all leukocyte surfaces, constituted by two monomers of molecular mass of ∼ 120-kDa (Moore et al 1992). A human soluble SELPLG has been described which is released after leukocyte activation (Davenpeck et al 2000).…”