MERS-CoV ORF4b employs an unusual binding mechanism to target IMPα and block innate immunity.
MERS-CoV ORF4b employs an unusual binding mechanism to target IMPα and block innate immunity.
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DOI：
10.1038/s41467-022-28851-2
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发表时间：
2022-03-25
影响因子：
16.6
通讯作者：
Forwood JK
中科院分区：
文献类型：
--
作者：
Munasinghe TS;Edwards MR;Tsimbalyuk S;Vogel OA;Smith KM;Stewart M;Foster JK;Bosence LA;Aragão D;Roby JA;Basler CF;Forwood JK
MERS冠状病毒（MERS-CoV）是一种高致病性的新兴病毒，可产生辅助蛋白来拮抗宿主的先天免疫反应。MERS-CoV ORF 4 b蛋白已被证明优先与感染细胞中的核输入衔接子IMPα3结合，从而抑制NF-κ B依赖性先天免疫应答。在这里，我们报告了与两个不同IMPα家族成员结合的ORF 4 b的高分辨率结构。每一个表现出高度相似的结合机制，在这两种情况下，缺乏一个原型的赖氨酸结合在其P2位点。NLS区域内的突变显著改变了结合机制，其恢复为经典的P2 Lys结合机制。突变研究证实，这种新型结合机制对其核输入、IMPα相互作用和抑制先天免疫信号传导途径至关重要。同时，我们确定了与IMPα2和α3结合的NF-κB组分p50的核结合结构域的结构，表明p50与ORF 4 B结合位点重叠，这表明了抑制的基础。我们的研究结果提供了详细的结构基础，解释了病毒如何靶向IMPα核输入衔接子以损害免疫力，并说明了ORF 4 b中的小突变，如在密切相关的冠状病毒如HKU 5中发现的突变，如何改变IMPα结合机制。MERS-CoV ORF 4 B部分通过阻断核输入接头IMPα活性和阻止NF-κB核转位来拮抗宿主先天性免疫应答。在这里，Munasinghe和Edwards等人从生物化学和结构上定义了ORF 4 b和IMPα-家族成员之间的相互作用，并发现ORF 4 b NLS与IMPα2和IMPα3之间存在非经典相互作用。
The MERS coronavirus (MERS-CoV) is a highly pathogenic, emerging virus that produces accessory proteins to antagonize the host innate immune response. The MERS-CoV ORF4b protein has been shown to bind preferentially to the nuclear import adapter IMPα3 in infected cells, thereby inhibiting NF-κB-dependent innate immune responses. Here, we report high-resolution structures of ORF4b bound to two distinct IMPα family members. Each exhibit highly similar binding mechanisms that, in both cases, lack a prototypical Lys bound at their P2 site. Mutations within the NLS region dramatically alter the mechanism of binding, which reverts to the canonical P2 Lys binding mechanism. Mutational studies confirm that the novel binding mechanism is important for its nuclear import, IMPα interaction, and inhibition of innate immune signaling pathways. In parallel, we determined structures of the nuclear binding domain of NF-κB component p50 bound to both IMPα2 and α3, demonstrating that p50 overlaps with the ORF4b binding sites, suggesting a basis for inhibition. Our results provide a detailed structural basis that explains how a virus can target the IMPα nuclear import adapter to impair immunity, and illustrate how small mutations in ORF4b, like those found in closely related coronaviruses such as HKU5, change the IMPα binding mechanism. MERS-CoV ORF4b antagonizes host innate immune response, partially via blocking nuclear import adapter IMPα activity and preventing nuclear translocation of NF-κB. Here, Munasinghe and Edwards et al. biochemically and structurally define the interaction between ORF4b and IMPα-family members and find a non-canonical interaction between ORF4b NLS and IMPα2 and IMPα3.
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DOI：
10.1107/s090744491003982x
发表时间：
2011-04
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Evans PR
通讯作者：
Evans PR
影响因子：
16.6
作者：
Jagga B;Edwards M;Pagin M;Wagstaff KM;Aragão D;Roman N;Nanson JD;Raidal SR;Dominado N;Stewart M;Jans DA;Hime GR;Nicolis SK;Basler CF;Forwood JK
通讯作者：
Forwood JK
影响因子：
14.9
作者：
Lefkowitz EJ;Dempsey DM;Hendrickson RC;Orton RJ;Siddell SG;Smith DB
通讯作者：
Smith DB
影响因子：
3.7
作者：
Mobaraki, Kazhal;Ahmadzadeh, Jamal
通讯作者：
Ahmadzadeh, Jamal
影响因子：
6.4
作者：
Gusho E;Zhang R;Jha BK;Thornbrough JM;Dong B;Gaughan C;Elliott R;Weiss SR;Silverman RH
通讯作者：
Silverman RH