Thrombin interaction with platelet membrane glycoprotein Ibα

The interaction of thrombin with platelet glycoprotein Ibα (GPIbα) is required for optimal platelet activation. The crystal structures of platelet GPIbα bound to thrombin reported by Dumas et al. and Celikel et al. both reveal the simultaneous interaction of GPIbα with thrombin exosites I and II but differ markedly regarding how the two proteins interact. The possible consequences on thrombus formation of thrombin interacting with GPIbα are discussed in light of these new data.