Proteolytic processing, deubiquitinase and interferon antagonist activities of Middle East respiratory syndrome coronavirus papain-like protease
Proteolytic processing, deubiquitinase and interferon antagonist activities of Middle East respiratory syndrome coronavirus papain-like protease
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中东呼吸综合征冠状病毒木瓜蛋白酶样蛋白酶的蛋白水解加工、去泛素酶和干扰素拮抗剂活性
DOI：
10.1099/vir.0.059014-0
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发表时间：
2014-03-01
影响因子：
3.8
通讯作者：
Chen, Zhongbin
中科院分区：
文献类型：
--
作者：
Yang, Xingxing;Chen, Xiaojuan;Chen, Zhongbin
新出现的中东呼吸综合征冠状病毒（MERS-CoV）导致人类严重的肺部疾病，是继严重急性呼吸综合征冠状病毒（SARS-CoV）之后的第二种高致病性冠状病毒（Coy）。基因组研究表明，两种病毒蛋白酶，木瓜蛋白酶样蛋白酶（PLpro）和3C样蛋白酶（3CLpro），处理由MERS-CoV基因组RNA编码的多蛋白。我们先前报道了SARS-CoV PLpro作为去泛素化酶（DUB）和IFN拮抗剂，但对MERS-CoV PLpro的功能知之甚少。在这项研究中，我们表征了MERS-CoV PLpro，它是一种蛋白酶，可以识别和处理nsp 1 -2，nsp 2 -3和nsp 3 -4的切割位点（CS）。pp 1a/1ab N末端的LXGG共有切割位点通常是CoV PLpro介导的加工所必需的，也在MERS-CoV中进行了表征。MERS-CoV PLpro与人SARS-CoV PLpro和NL 63-CoV PLP 2一样，是一种病毒去泛素化酶。它作用于K48和K63连接的泛素化和ISG 15连接的ISG化。我们证实MERS-CoV PLpro通过阻断IFN调节因子3（IRF 3）的磷酸化和核转位而作为IFN拮抗剂。这些发现表明，MERS-CoV PLpro作为病毒DUB并通过干扰IRF 3介导的信号传导途径抑制IFN-β的产生，此外还识别和加工复制酶多聚蛋白N末端的CS以释放非结构蛋白。对MERS-CoV PLpro蛋白的蛋白水解、DUB和IFN拮抗活性的研究将揭示MERS-CoV与宿主之间的相互作用，为开发针对PLpro的有效控制MERS-CoV感染的策略提供理论依据。
The emerging Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe pulmonary disease in humans and represents the second example of a highly pathogenic coronavirus (Coy) following severe acute respiratory syndrome coronavirus (SARS-CoV). Genomic studies revealed that two viral proteases, papain-like protease (PLpro) and 3C-like protease (3CLpro), process the polyproteins encoded by the MERS-CoV genomic RNA. We previously reported that SARS-CoV PLpro acts as both deubiquitinase (DUB) and IFN antagonist, but the function of the MERS-CoV PLpro was poorly understood. In this study, we characterized MERS-CoV PLpro, which is a protease and can recognize and process the cleavage sites (CS) of nsp1-2, nsp2-3 and nsp3-4. The LXGG consensus cleavage sites in the N terminus of pp1a/1ab, which is generally essential for CoV PLpro-mediated processing, were also characterized in MERS-CoV. MERS-CoV PLpro, like human SARS-CoV PLpro and NL63-CoV PLP2, is a viral deubiquitinating enzyme. It acts on both K48- and K63-linked ubiquitination and ISG15-linked ISGylation. We confirmed that MERS-CoV PLpro acts as an IFN antagonist through blocking the phosphorylation and nuclear translocation of IFN regulatory factor 3 (IRF3). These findings indicate that MERS-CoV PLpro acts as a viral DUB and suppresses production of IFN-beta by an interfering IRF3-mediated signalling pathway, in addition to recognizing and processing the CS at the N terminus of replicase polyprotein to release the non-structural proteins. The characterization of proteolytic processing, DUB and IFN antagonist activities of MERS-CoV PLpro would reveal the interactions between MERS-CoV and its host, and be applicable to develop strategies targeting PLpro for the effective control of MERS-CoV infection.