Determinants of the Specificity of Rotavirus Interactions with the α2β1 Integrin
Determinants of the Specificity of Rotavirus Interactions with the α2β1 Integrin
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DOI：
10.1074/jbc.m110.142992
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发表时间：
2011-02-25
影响因子：
4.8
通讯作者：
Coulson, Barbara S.
中科院分区：
文献类型：
--
作者：
Fleming, Fiona E.;Graham, Kate L.;Coulson, Barbara S.
人α 2 β 1整联蛋白结合胶原蛋白并作为轮状病毒和人埃可病毒1的细胞受体。这些配体需要在α 2 β 1的α 2亚基内插入（I）结构域以用于结合。先前的研究已经确定了α 2 I结构域中胶原和埃可病毒1的结合位点。我们使用表达突变的α 2 β 1的CHO细胞来鉴定与人和动物轮状病毒结合的氨基酸。突变影响轮状病毒结合的残基位于α 2 I结构域的几个暴露环和相邻区域。所有轮状病毒的结合通过激活响应性α C-α 6和α F螺旋中的突变而消除。这是区分轮状病毒与其他α 2 β 1配体的新特征。与金属离子（α 2中的Ser-153、Thr-221和Glu-256以及β 1中的Asp-130）和附近氨基酸（Ser-154、Gln-215和Asp-219）协调的残基突变也抑制轮状病毒结合。大多数这些残基的重要性是最大的结合人轮状病毒。这些突变抑制胶原蛋白与α 2 β 1结合（除了Glu-256），但不影响埃可病毒结合。总的来说，突变影响轮状病毒和胶原蛋白识别的残基位于金属离子依赖性粘附位点的一侧，而那些对胶原蛋白很重要的残基则聚集在附近。消除轮状病毒和埃可病毒结合的突变是不同的，与这些病毒对活化或失活α 2 β 1的各自偏好一致。相反，轮状病毒和胶原蛋白利用活化的α 2 β 1，并显示出对结合重要的α 2 β 1残基的重叠。
The human alpha 2 beta 1 integrin binds collagen and acts as a cellular receptor for rotaviruses and human echovirus 1. These ligands require the inserted (I) domain within the alpha 2 subunit of alpha 2 beta 1 for binding. Previous studies have identified the binding sites for collagen and echovirus 1 in the alpha 2 I domain. We used CHO cells expressing mutated alpha 2 beta 1 to identify amino acids involved in binding to human and animal rotaviruses. Residues where mutation affected rotavirus binding were located in several exposed loops and adjacent regions of the alpha 2 I domain. Binding by all rotaviruses was eliminated by mutations in the activation-responsive alpha C-alpha 6 and alpha F helices. This is a novel feature that distinguishes rotavirus from other alpha 2 beta 1 ligands. Mutation of residues that co-ordinate the metal ion (Ser-153, Thr-221, and Glu-256 in alpha 2 and Asp-130 in beta 1) and nearby amino acids (Ser-154, Gln-215, and Asp-219) also inhibited rotavirus binding. The importance of most of these residues was greatest for binding by human rotaviruses. These mutations inhibit collagen binding to alpha 2 beta 1 (apart from Glu-256) but do not affect echovirus binding. Overall, residues where mutation affected both rotavirus and collagen recognition are located at one side of the metal ion-dependent adhesion site, whereas those important for collagen alone cluster nearby. Mutations eliminating rotavirus and echovirus binding are distinct, consistent with the respective preference of these viruses for activated or inactive alpha 2 beta 1. In contrast, rotavirus and collagen utilize activated alpha 2 beta 1 and show an overlap in alpha 2 beta 1 residues important for binding.