von Willebrand factor binds to native collagen VI primarily via its A1 domain
von Willebrand factor binds to native collagen VI primarily via its A1 domain
复制标题
DOI：
10.1042/bj3240185
复制
发表时间：
1997-05-15
影响因子：
4.1
通讯作者：
Vermylen, J
中科院分区：
文献类型：
--
作者：
Hoylaerts, MF;Yamamoto, H;Vermylen, J
VI型胶原在动脉内皮下丰富。为了研究其与血管性血友病因子（vWF）相互作用的机制，从人胎盘和人肺成纤维细胞系MRC-5的细胞外基质中分离胶原VI。纯化的vWF以中等高的亲和力（EC 50约为5 nM）与未消化的胶原VI结合，并可被水蛭胶原抑制剂calin抑制。抗（人vWF A1结构域）单克隆抗体（AJvW-2）以及金精三羧酸（ATA）在饱和vWF A1结构域的浓度下也抑制这种结合。相反，单克隆抗（人vWF A3结构域）抗体（82 D 6A 3）抑制vWF与胶原蛋白I、III和IV的结合，但对vWF与胶原蛋白VI的结合没有影响。同样，vWF与胶原VI的结合不受重组vWF结构域D4的抑制。多克隆抗（胶原VI）抗体，特异性中和vWF的胶原VI的结合，证实了在完整的内皮细胞细胞外基质，胶原VI是访问与vWF的相互作用。这种结合仅受到82 D 6A 3的轻微影响，但受到AJvW-2、ATA和Al结构域类似物VCL（vWF的重组A1结构域）的剂量依赖性抑制，IC 50值与抑制vWF与分离的胶原VI结合的IC 50值相当。分离的人血小板与胶原蛋白VI的弱相互作用是通过血小板胶原蛋白受体（GPIa/IIa）介导的，并且被vWF而不是VCL竞争性抑制，这表明vWF和GPIa/IIa与胶原蛋白VI上的相邻但不同的位点结合。我们得出结论，vWF结合胶原VI主要是通过其A1域，这将其与vWF A3域介导的纤维状胶原结合区分开来。
Collagen VI is abundant in the arterial subendothelium. To investigate its mechanism of interaction with von Willebrand factor (vWF), collagen VI was isolated from human placenta and from the extracellular matrix of the human lung fibroblast cell line MRC-5. Purified vWF bound to non-digested collagen VI with moderately high affinity (EC50 approximate to 5 nM) and could be inhibited by the Hirudo medicinalis collagen inhibitor calin. The anti-(human vWF A1 domain) monoclonal antibody (AJvW-2), as well as aurin tricarboxylic acid (ATA), at concentrations that saturate the vWF Al domain, also inhibited this binding. In contrast, the monoclonal anti-(human vWF A3 domain) antibody (82D6A3) inhibited vWF binding to collagens I, III and IV, but had no effect on vWF binding to collagen VI. Likewise, vWF binding to collagen VI was not inhibited by the recombinant vWF domain D4. Polyclonal anti-(collagen VI) antibodies, specifically neutralizing the binding of vWF to collagen VI, confirmed that in the intact endothelial cell extracellular matrix, collagen VI was accessible for interaction with vWF. This binding was only marginally affected by 82D6A3 but was dose-dependently inhibited by AJvW-2, ATA and the Al domain analogue VCL (recombinant A1 domain of vWF), with IC50 values comparable to those found for the inhibition of vWF binding to isolated collagen VI. The weak interaction of isolated human platelets with collagen VI was mediated via the platelet collagen receptor (GPIa/IIa) and was competitively inhibited by vWF but not by VCL, suggesting that vWF and GPIa/IIa bind to neighbouring but distinct sites on collagen VI. We conclude that vWF binds to collagen VI primarily via its A1 domain, which distinguishes it from the vWF A3 domain-mediated binding to fibrillar collagens.