Analysis of the roles of 14-3-3 in the platelet glycoprotein Ib-IX-mediated activation of integrin alpha(IIb)beta(3) using a reconstituted mammalian cell expression model.
Analysis of the roles of 14-3-3 in the platelet glycoprotein Ib-IX-mediated activation of integrin alpha(IIb)beta(3) using a reconstituted mammalian cell expression model.
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分析使用重构的哺乳动物细胞表达模型，对整联蛋白α（IIB）β（3）的血小板糖蛋白IB-IX介导的激活的作用分析。
DOI：
10.1083/jcb.147.5.1085
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发表时间：
1999-11-29
影响因子：
7.8
通讯作者：
Du, X
中科院分区：
文献类型：
--
作者：
Gu, M;Xi, X;Englund, G D;Berndt, M C;Du, X
我们在重组DNA表达模型中重建了血小板糖蛋白（GP）Ib-IX介导的整合素αIIbβ3的活化，并表明14-3-3在GPIb-IX信号传导中是重要的。表达αIIbβ3的CHO细胞与vWF的粘附较差。表达GPIb-IX的细胞在botrocetin存在下粘附于vWF，但扩散较差。共表达整合素αIIbβ3和GPIb-IX的细胞在vWF上粘附和扩散，vWF可被RGDS肽和抗αIIbβ3的抗体抑制。vWF与GPIb-IX的结合也激活可溶性纤维蛋白原与αIIbβ3的结合，表明GPIb-IX介导导致αIIbβ3激活的细胞信号。GPIbα中14-3-3-结合位点的缺失抑制GPIb-IX介导的纤维蛋白原与αIIbβ3的结合和vWF上的细胞铺展。因此，14-3-3与GPIb-IX的结合在GPIb-IX信号传导中是重要的。显性负性14-3-3突变体的表达抑制了vWF上的细胞铺展，表明14-3-3的重要作用。删除GPIbα的14-3-3和细丝蛋白结合位点可诱导内源性整合素依赖性细胞在vWF上扩散，而不需要αIIbβ3，但可抑制vWF诱导的纤维蛋白原与αIIbβ3的结合。因此，虽然不同的激活机制可能是vWF与不同整合素相互作用的原因，但GPIb-IX介导的αIIbβ3激活需要14-3-3与GPIbα相互作用。
We have reconstituted the platelet glycoprotein (GP) Ib-IX–mediated activation of the integrin αIIbβ3 in a recombinant DNA expression model, and show that 14-3-3 is important in GPIb-IX signaling. CHO cells expressing αIIbβ3 adhere poorly to vWF. Cells expressing GPIb-IX adhere to vWF in the presence of botrocetin but spread poorly. Cells coexpressing integrin αIIbβ3 and GPIb-IX adhere and spread on vWF, which is inhibited by RGDS peptides and antibodies against αIIbβ3. vWF binding to GPIb-IX also activates soluble fibrinogen binding to αIIbβ3 indicating that GPIb-IX mediates a cellular signal leading to αIIbβ3 activation. Deletion of the 14-3-3–binding site in GPIbα inhibited GPIb-IX–mediated fibrinogen binding to αIIbβ3 and cell spreading on vWF. Thus, 14-3-3 binding to GPIb-IX is important in GPIb-IX signaling. Expression of a dominant negative 14-3-3 mutant inhibited cell spreading on vWF, suggesting an important role for 14-3-3. Deleting both the 14-3-3 and filamin-binding sites of GPIbα induced an endogenous integrin-dependent cell spreading on vWF without requiring αIIbβ3, but inhibited vWF-induced fibrinogen binding to αIIbβ3. Thus, while different activation mechanisms may be responsible for vWF interaction with different integrins, GPIb-IX–mediated activation of αIIbβ3 requires 14-3-3 interaction with GPIbα.