GPVI receptor has little affinity for soluble forms of collagen but binds collagen fibrils. Recent structural models indicate that each GPVI receptor complex could bind up to 3 collagen fibrils (Jung & Moroi 2008). The Src family kinases Fyn and Lyn constitutively associate with the GPVI-FceRIgamma complex in platelets and initiate platelet activation through phosphorylation of the immunoreceptor tyrosine-based activation motif (ITAM) in the FceRIgamma chain, leading to binding and activation of the tyrosine kinase Syk. Downstream of Syk, a series of adapter molecules and effectors lead to platelet activation.