Glycosylation of high-affinity thrombin receptors appears necessary for thrombin binding.
Monosaccharide binding competition, lectin affinity chromatography, and glycosylation inhibitors have been used to determine if glycosylation plays a role in thrombin-receptor interactions. Mannose appeared to specifically inhibit thrombin binding to mouse embryo (ME) and hamster fibroblasts. Concanavalin A bound to antibody-purified receptor fractions, and was used as an affinity ligand to purify receptor fractions that retained thrombin binding activity. Cells treated with tunicamycin (6.25 ng/ml) for 24 h lost approximately 35% of their high-affinity thrombin binding sites, yet binding of receptor monoclonal antibody TR-9 was not affected, indicating that the receptor was present in the membrane, but unable to bind thrombin. Thus thrombin receptor glycosylation may be directly involved in thrombin binding.
Frost
G H
GH
Department of Human Biological Chemistry and Genetics, University of Texas Medical Branch, Galveston 77550.
Bergmann
J S
JS
Carney
D H
DH
D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002846:Chromatography, Affinity; D003208:Concanavalin A / Q000378:metabolism; D006224:Cricetinae; D005347:Fibroblasts / Q000378:metabolism; D006031:Glycosylation; D051379:Mice; D008813:Mice, Inbred ICR; D009005:Monosaccharides / Q000494:pharmacology; D011956:Receptors, Cell Surface / Q000302:isolation & purification / Q000378:metabolism*; D018179:Receptors, Thrombin; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014415:Tunicamycin / Q000494:pharmacology
D009005:Monosaccharides; D011956:Receptors, Cell Surface; D018179:Receptors, Thrombin; D003208:Concanavalin A; D014415:Tunicamycin; D013917:Thrombin