Ligand-Binding Assays for Collagen

Collagen is one of the most physiologically important agonists for platelet function. Two collagen-specific receptors, integrin α₂ β₁ and glycoprotein (GP) VI, have been identified on the platelet surface from studying patient’s platelets deficient in one of these proteins (1 ,2 ). Integrin α₂ β₁ was found to be the major receptor responsible for platelet adhesion to collagen (3 ,4 ). The other collagen receptor, GPVI, was indicated to contribute to platelet activation and aggregation by its involvement in collagen-induced signaling pathways (5 ,6 ).