Regulation of von Willebrand factor finding to the platelet glycoprotein Ib-IX by a membrane skeleton-dependent inside-out signal
Regulation of von Willebrand factor finding to the platelet glycoprotein Ib-IX by a membrane skeleton-dependent inside-out signal
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DOI：
10.1074/jbc.m008048200
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发表时间：
2001-05-18
影响因子：
4.8
通讯作者：
Du, XP
中科院分区：
文献类型：
--
作者：
Englund, GD;Bodnar, RJ;Du, XP
血管性血友病因子（vWF）的血小板受体，糖蛋白Ib-M（GPIb-IX），介导初始血小板粘附和活化。我们在这里表明，GPIb-IX的受体功能调节细胞内通过其连接到细丝蛋白相关的膜骨架。GPib α中细丝蛋白结合位点的缺失显着增强了瑞斯托菌素（或肉毒素）诱导的vWF结合，并允许表达GPIb-IX的细胞在静态和流动条件下粘附于固定的vWF。解聚肌动蛋白的细胞松弛素D（CD）也增强vWF与野生型GPIb-IX的结合。因此，VWF与GPIb-IX的结合受到细丝蛋白相关膜骨架的负调控。与天然vWF相反，分离的重组vWF Al结构域与GPIb-IX的野生型和细丝蛋白结合缺陷突变体的结合是相当的，这表明膜粘附子相关的GPIb-IX处于阻止进入大分子vWF中的Al结构域的状态。在血小板中，存在膜粘附子相关的GPIb-IX和游离形式的GPIb-IX的平衡。用CD处理血小板增加了游离形式并增强了vWF结合。CD还逆转前列腺素El对vWF与GPIb-IX结合的抑制作用。因此，GPIb-IX依赖性血小板粘附是由vWF构象和膜粘附子依赖性由内而外信号双重控制的。
The platelet receptor for von Willebrand factor (vWF), glycoprotein Ib-M (GPIb-IX), mediates initial platelet adhesion and activation. We show here that the receptor function of GPIb-IX is regulated intracellularly via its link to the filamin-associated membrane skeleton. Deletion of the filamin binding site in GPIb alpha markedly enhances ristocetin- (or botrocetin)-induced vWF binding and allows GPIb-IX-expressing cells to adhere to immobilized vWF under both static and flow conditions. Cytochalasin D (CD) that depolymerizes actin also enhances vWF binding to wild type GPIb-IX, Thus, VWF binding to GPIb-IX is negatively regulated by the filamin-associated membrane skeleton. In contrast to native vWF, binding of the isolated recombinant vWF Al domain to wild type and filamin binding-deficient mutants of GPIb-IX is comparable, suggesting that the membrane skeleton-associated GPIb-IX is in a state that prevents access to the Al domain in macromolecular vWF, In platelets, there is a balance of membrane skeleton-associated and free forms of GPIb-IX. Treatment of platelets with CD increases the free form and enhances vWF binding. CD also reverses the inhibitory effects of prostaglandin El on vWF binding to GPIb-IX. Thus, GPIb-IX-dependent platelet adhesion is doubly controlled by vWF conformation and a membrane skeleton-dependent inside-out signal.