Receptor binding domain of SARS-CoV-2 is a functional αv-integrin agonist.
Receptor binding domain of SARS-CoV-2 is a functional αv-integrin agonist.
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SARS-CoV-2 的受体结合域是一种功能性 αv 整合素激动剂。
DOI：
10.1101/2022.04.11.487882
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Hocking,DeniseC
中科院分区：
文献类型：
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作者：
Norris,EmmaG;Pan,XuanSabrina;Hocking,DeniseC
在SARS-CoV-2与类似冠状病毒的新突变中，病毒刺突（S）蛋白S1区的受体结合结构域（RBD）中的K403 R取代。这种氨基酸取代发生在血管紧张素转化酶2结合界面附近，并产生了一个典型的RGD粘附基序，该基序通常存在于天然细胞外基质蛋白（包括纤连蛋白）中。在这里，重组S1-RBD结合细胞表面整合素和触发下游信号传导途径的能力进行了评估，并与含RGD的纤连蛋白整合素结合片段进行了比较。我们确定S1-RBD支持纤连蛋白缺失小鼠胚胎成纤维细胞以及原代人小气道上皮细胞的粘附，而RBD包被的微粒以阳离子依赖性方式附着于上皮单层。细胞与S1-RBD的粘附是依赖于RGD的，可被α v和β 3的阻断抗体抑制，但不被α 5或β 1的阻断抗体抑制。同样，我们用表面等离子体共振技术观察到S1-RBD与重组人αvβ 3和αvβ 6整合素直接结合，而与α5β 1整合素不结合。S1-RBD粘附引发细胞铺展、粘着斑形成和肌动蛋白应力纤维组织，其程度与纤连蛋白相似。此外，S1-RBD刺激粘附介质FAK、Src和桩蛋白的酪氨酸磷酸化;触发Akt活化;并支持细胞增殖。因此，S1-RBD的RGD序列可以作为α v-选择性整联蛋白激动剂发挥作用。这项研究提供了证据表明，细胞表面α v整合素可以功能性地响应刺突蛋白，并提出了S1介导的细胞外基质动力学失调可能有助于SARS-CoV-2感染的发病机制和/或急性后后遗症的可能性。
Among the novel mutations distinguishing SARS-CoV-2 from similar coronaviruses is a K403R substitution in the receptor-binding domain (RBD) of the viral spike (S) protein within its S1 region. This amino acid substitution occurs near the angiotensin-converting enzyme 2–binding interface and gives rise to a canonical RGD adhesion motif that is often found in native extracellular matrix proteins, including fibronectin. Here, the ability of recombinant S1-RBD to bind to cell surface integrins and trigger downstream signaling pathways was assessed and compared with RGD-containing, integrin-binding fragments of fibronectin. We determined that S1-RBD supported adhesion of fibronectin-null mouse embryonic fibroblasts as well as primary human small airway epithelial cells, while RBD-coated microparticles attached to epithelial monolayers in a cation-dependent manner. Cell adhesion to S1-RBD was RGD dependent and inhibited by blocking antibodies against αvand β3but not α5or β1integrins. Similarly, we observed direct binding of S1-RBD to recombinant human αvβ3and αvβ6integrins, but not α5β1integrins, using surface plasmon resonance. S1-RBD adhesion initiated cell spreading, focal adhesion formation, and actin stress fiber organization to a similar extent as fibronectin. Moreover, S1-RBD stimulated tyrosine phosphorylation of the adhesion mediators FAK, Src, and paxillin; triggered Akt activation; and supported cell proliferation. Thus, the RGD sequence of S1-RBD can function as an αv-selective integrin agonist. This study provides evidence that cell surface αv-containing integrins can respond functionally to spike protein and raises the possibility that S1-mediated dysregulation of extracellular matrix dynamics may contribute to the pathogenesis and/or post-acute sequelae of SARS-CoV-2 infection.