Gain of von Willebrand factor-binding function by mutagenesis of a species-conserved residue within the leucine-rich repeat region of platelet glycoprotein Ibα
Gain of von Willebrand factor-binding function by mutagenesis of a species-conserved residue within the leucine-rich repeat region of platelet glycoprotein Ibα
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DOI：
10.1182/blood-2005-02-0514
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发表时间：
2005-09-15
期刊：
影响因子：
20.3
通讯作者：
López, JA
中科院分区：
文献类型：
--
作者：
Peng, YD;Shrimpton, CN;López, JA
糖蛋白（GP） Ib α是富亮氨酸重复序列（LRR）蛋白家族的一员，可介导血小板对固定化血管性血友病因子（VWF）的粘附。我们研究了GP lb α LRR区带电残基在VWF结合中的作用，这些残基在人、犬和鼠蛋白中是保守的。用Ala或Glu替代His86可以增强VWF的结合功能，这可以通过在瑞斯托素和乳素的存在下增加VWF的结合以及在流动条件下表达突变体GP lb α的中国仓鼠卵巢（CHO）细胞对固定VWF的粘附增强来判断。这是首次报道GP Ib α LRR区突变导致的功能获得表型。由于HIs86距离GP Ib α与VWF接触面最大的区域2 nm，数据表明LRRs对GP Ib α对VWF的亲和力进行了变变调节。
Glycoprotein (GP) Ib alpha, a member of the leucine-rich repeat (LRR) protein family, mediates platelet adhesion to immobilized von Willebrand factor (VWF). We investigated the role in VWF binding of charged residues in the LRR region of GP lb alpha that are conserved in human, canine, and murine proteins. Substitution of His86 with either Ala or Glu resulted in a gain of VWF-binding function as judged by increased VWF binding in the presence of the modulators ristocetin and botrocetin and by enhanced adhesion of Chinese hamster ovary (CHO) cells expressing the mutant GP lb alpha to immobilized VWF under conditions of flow. This is the first report of a gain-of-function phenotype resulting from mutations in the LRR region of GP Ib alpha. Because HIs86 is 2 nm away from the region of GP Ib alpha with the largest surface of contact with VWF, the data suggest that the LRRs regulate GP Ib alpha affinity for VWF allosterically.