Analysis of inter-subunit contacts reveals the structural malleability of extracellular domains in platelet glycoprotein Ib-IX complex.
Analysis of inter-subunit contacts reveals the structural malleability of extracellular domains in platelet glycoprotein Ib-IX complex.
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DOI：
10.1111/jth.12437
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发表时间：
2014-01
期刊：
影响因子：
--
通讯作者：
Li R
中科院分区：
文献类型：
--
作者：
Zhou L;Yang W;Li R
糖蛋白（GP）Ib-IX复合物对止血和血栓形成至关重要。它的正确组装与其表面表达水平密切相关，并且需要Ibα、Ibβ和IX亚基的胞外和跨膜结构域之间的协同相互作用。先前已经确定了Ibβ和IX的细胞外结构域之间的两个界面。了解细胞外结构域如何在GPIb-IX中相互作用。将GPIb-IX中的Ibβ细胞外结构域（Ibβ e）或IX对应物（IXE）替换为折叠良好的Ibβ e /IXE嵌合体，称为Ibβ eabc，并分析了结构域替换对短暂转染的中国仓鼠卵巢细胞中受体复合物组装和表达的影响。用IbβEabc替代IXE后，GPIb-IX保留了胞外结构域之间的界面1，但未保留界面2。虽然这种结构域替换保留了复合物的完整性，但Ibβ和Ibα的表达水平显著降低。GPIb-IX中IbβEabc或IbβE的额外结构域替换产生了不同表达水平的复合物，这不能简单地用两个单独的接口来解释。特别是，当IbβEabc取代GPIb-IX中的IbβE时，Ibα和IX的表达量约为野生型的70%。当IXE进一步改变为IbβE时，它们的水平并未降低。我们的研究结果证明了Ibβ和IX胞外结构域之间的关联对于复杂的组装和高效表达的重要性，并为这些结构域的结构延展性提供了证据，这些结构域可以容纳和传播其中的构象变化。
The glycoprotein (GP)Ib-IX complex is critical to hemostasis and thrombosis. Its proper assembly is closely correlated with its surface expression level and requires cooperative interactions among extracellular and transmembrane domains of Ibα, Ibβ and IX subunits. Two interfaces have been previously identified between the extracellular domains of Ibβ and IX. To understand how extracellular domains interact in GPIb-IX. The Ibβ extracellular domain (IbβE) or the IX counterpart (IXE) in GPIb-IX was replaced with a well-folded IbβE/IXE chimera called IbβEabc, and the effect of domain replacement on assembly and expression of the receptor complex in transiently transfected Chinese hamster ovary cells was analyzed. Replacing IXE with IbβEabc in GPIb-IX retained interface 1 but not interface 2 between the extracellular domains. While this domain replacement preserved complex integrity, the expression levels of Ibβ and Ibα were significantly reduced. Additional domain replacement with IbβEabc or IbβE in GPIb-IX produced the complex at disparate expression levels that cannot be simply explained by two separate interfaces. In particular, when IbβE in GPIb-IX was replaced by IbβEabc, Ibα and IX were expressed at approximately 70% of the wild-type level. Their levels were not reduced when IXE was changed further to IbβE. Our results demonstrate the importance of the association between Ibβ and IX extracellular domains for complex assembly and efficient expression, and provide evidence for the structural malleability of these domains that may accommodate and propagate conformational changes therein.
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DOI：
10.1111/jth.12144
发表时间：
2013-04
期刊：
Journal of thrombosis and haemostasis : JTH
影响因子：
--
作者：
Li R;Emsley J
通讯作者：
Emsley J
影响因子：
20.3
作者：
Kato, K;Martinez, C;Ware, J
通讯作者：
Ware, J
DOI：
10.1161/atvbaha.112.301013
发表时间：
2013-06-01
影响因子：
8.7
作者：
Maurer, Eric;Tang, Chaojun;Mangin, Pierre H.
通讯作者：
Mangin, Pierre H.
影响因子：
4.8
作者：
Mo, Xi;Lu, Nan;Li, Renhao
通讯作者：
Li, Renhao
影响因子：
20.3
作者：
Perrault, C;Mangin, P;Lanza, F
通讯作者：
Lanza, F