Glycoprotein VI Is a Major Collagen Receptor for Platelet Activation: It Recognizes the Platelet-Activating Quaternary Structure of Collagen, Whereas CD36, Glycoprotein IIb/IIIa, and von Willebrand Factor Do Not

作者：Beate E. Kehrel, Sonja Wierwille, Kenneth J. Clemetson, Olaf Anders, Michael Steiner, Christopher G. Knight, Richard W. Farndale, Minoru Okuma, Michael J. Barnes · 发表于：Blood · 年份：1998 · DOI：10.1182/blood.v91.2.491 · 被引用次数：324 · 研究领域：Platelet Disorders and Treatments、Cell Adhesion Molecules Research、Heparin-Induced Thrombocytopenia and Thrombosis

Simple collagen-related peptides (CRPs) containing a repeat Gly-Pro-Hyp sequence are highly potent platelet agonists. Like collagen, they must exhibit tertiary (triple-helical) and quaternary (polymeric) structure to activate platelets. Platelet signaling events induced by the peptides are the same as most of those induced by collagen. The peptides do not recognize the alpha 2 beta 1 integrin. To identify the signaling receptor involved, we have evaluated the response to the CRP, Gly-Lys-Hyp(Gly-Pro-Hyp)10-Gly-Lys-Hyp-Gly of platelets with defined functional deficiencies. These studies exclude a primary recognition role for CD36, von Willebrand factor (vWF), or glycoprotein (GP) IIb/IIIa. Thus, both CD36 and vWF-deficient platelets exhibited normal aggregation, normal fibrinogen binding, and normal expression of CD62 and CD63, measured by flow cytometry, in response to the peptide, and there was normal expression of CD62 and CD63 on thrombasthenic platelets. In contrast, GPVI-deficient platelets were totally unresponsive to the peptide, indicating that this receptor recognizes the Gly-Pro-Hyp sequence in collagen. GPVI-deficient platelets showed some fibrinogen binding in response to collagen but failed to aggregate and to express CD62 and CD63. Collagen, but not CRP-XL, contains binding sites for alpha 2 beta 1. Therefore, it is possible that collagen still induces some signaling via alpha 2 beta 1, leading to activation of GPIIb/IIIa. Our findings are consistent with a two-...