血小板粘附的启动是在血小板栓子形成的第一步。循环血小板被捕，随后通过暴露的胶原和vWF的激活。它并不完全清楚，其胶原的类型是负责粘附和活化;胶原I型和III是血管上皮细胞，但几种其它类型的incluing IV存在（Farndale 2006）丰富。数个胶原结合蛋白被表达在血小板上，包括整联蛋白α2β1，GPVI，和GPIV。整联蛋白α2β1，在白细胞上称为VLA-2，是主要的血小板胶原受体（Kunicki等人1988）。它需要的Mg2 +与胶原蛋白的相互作用，并可能需要通过整合素β3alphaIIb（范·德·2007 WALLE）的活化介导的启动。结合经由所述α-2亚单位结构域I的胶原基序与序列甘氨酸 - 苯丙氨酸 - 羟脯氨酸 - 甘氨酸 - 谷氨酸 - 精氨酸（Emsley表示2000年）进行。胶原蛋白α2到的β1的结合产生有助于血小板活化的细胞内信号。这些促进较低亲和力胶原受体的接合，GPVI（基利1996），参与胶原蛋白诱导的血小板活化的关键受体。 The GPVI receptor is a complex of the GPVI protein with a dimer of Fc epsilon R1 gamma (FceRI gamma). 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 FceRI gamma, leading to binding and activation of the tyrosine kinase Syk. Downstream of Syk, a series of adapter molecules and effectors lead to platelet activation. vWF protein is a polymeric structure of variable size. It is secreted in two directions, by the endothelium basolaterally and into the bloodstream. Shear-induced aggregation is achieved when vWF binds via its A1 domain to GPIb (part of GPIb-IX-V), and via its A3 domain mediating collagen binding to the subendothelium. The interaction between vWF and GPIb is regulated by shear force; an increase in the shear stress results in a corresponding increase in the affinity of vWF for GPIb.
