MARCH8 Inhibits Ebola Virus Glycoprotein, Human Immunodeficiency Virus Type 1 Envelope Glycoprotein, and Avian Influenza Virus H5N1 Hemagglutinin Maturation
MARCH8 Inhibits Ebola Virus Glycoprotein, Human Immunodeficiency Virus Type 1 Envelope Glycoprotein, and Avian Influenza Virus H5N1 Hemagglutinin Maturation
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MARCH8 抑制埃博拉病毒糖蛋白、人类免疫缺陷病毒 1 型包膜糖蛋白和禽流感病毒 H5N1 血凝素成熟
DOI：
10.1128/mbio.01882-20
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发表时间：
2020-09-01
期刊：
影响因子：
6.4
通讯作者：
Zheng, Yong-Hui
中科院分区：
文献类型：
--
作者：
Yu, Changqing;Li, Sunan;Zheng, Yong-Hui
膜相关环-CH-8(MARCH8)通过下调HIV-1包膜糖蛋白(Env)的细胞表面表达，强烈地阻止其进入病毒粒子，但其机制尚不清楚。我们现在报道，MARCH8还通过表面下调来阻止埃博拉病毒(EBOV)糖蛋白(GP)的掺入。为了了解这些病毒融合蛋白是如何下调的，我们通过传统的分泌途径研究了MARCH8对EBOV gp成熟和外化的影响。免疫沉淀法检测到MARCH8与EBOV gp和Furin相互作用，通过双分子荧光互补(BIFC)法追踪它们的位置时，MARCH8将gp/Furin复合体保留在高尔基体中。MARCH8不降低GP的表达，也不影响内质网(ER)中高甘露糖N-聚糖对GP的修饰，但它能抑制高尔基体GP上复杂N-聚糖的形成。此外，GP O-糖基化和呋喃介导的蛋白水解性切割也受到抑制。此外，我们在EBOV GP上发现了一个新的Furin裂解位点，并发现只有那些完全糖基化的GP才能被Furin处理并整合到病毒粒子中。此外，MARCH8对GP的释放和分泌均有抑制作用。MARCH8还阻断了呋喃介导的HIV-1Env(Gp160)和高致病性禽流感病毒H5N1血凝素(HA)的切割。我们认为，MARCH8具有广泛的抗病毒活性，通过阻止不同的病毒融合蛋白在高尔基体中的糖基化和蛋白水解性切割，从而抑制它们从高尔基体到质膜的运输和并入病毒粒子。重要包膜病毒表达三类融合蛋白，它们通过介导病毒和细胞膜融合进入宿主细胞。I类融合蛋白由流感病毒、逆转录病毒、埃博拉病毒和冠状病毒产生。它们首先作为I型跨膜多肽前体合成，然后糖基化和寡聚化。这些前体中的大多数在分泌晚期被细胞蛋白酶Furin切割到质膜上，产生三聚体N-端受体结合亚基和C-端融合亚基。在这里，我们显示了一种细胞蛋白MARCH8，它特异性地抑制了FURIN介导的EBOV GP、HIV-1 Env和H5N1 HA的切割。进一步的分析发现，MARCH8阻断了高尔基体中EBOV糖蛋白的糖基化，并抑制了其从高尔基体到质膜的运输。因此，MARCH8通过特异性灭活不同的病毒融合蛋白而具有非常广泛的抗病毒活性。
Membrane-associated RING-CH-type 8 (MARCH8) strongly blocks human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) incorporation into virions by downregulating its cell surface expression, but the mechanism is still unclear. We now report that MARCH8 also blocks the Ebola virus (EBOV) glycoprotein (GP) incorporation via surface downregulation. To understand how these viral fusion proteins are downregulated, we investigated the effects of MARCH8 on EBOV GP maturation and externalization via the conventional secretion pathway. MARCH8 interacted with EBOV GP and furin when detected by immunoprecipitation and retained the GP/furin complex in the Golgi when their location was tracked by a bimolecular fluorescence complementation (BiFC) assay. MARCH8 did not reduce the GP expression or affect the GP modification by high-mannose N-glycans in the endoplasmic reticulum (ER), but it inhibited the formation of complex N-glycans on the GP in the Golgi. Additionally, the GP O-glycosylation and furin-mediated proteolytic cleavage were also inhibited. Moreover, we identified a novel furin cleavage site on EBOV GP and found that only those fully glycosylated GPs were processed by furin and incorporated into virions. Furthermore, the GP shedding and secretion were all blocked by MARCH8. MARCH8 also blocked the furin-mediated cleavage of HIV-1 Env (gp160) and the highly pathogenic avian influenza virus H5N1 hemagglutinin (HA). We conclude that MARCH8 has a very broad antiviral activity by prohibiting different viral fusion proteins from glycosylation and proteolytic cleavage in the Golgi, which inhibits their transport from the Golgi to the plasma membrane and incorporation into virions.IMPORTANCE Enveloped viruses express three classes of fusion proteins that are required for their entry into host cells via mediating virus and cell membrane fusion. Class I fusion proteins are produced from influenza viruses, retroviruses, Ebola viruses, and coronaviruses. They are first synthesized as a type I transmembrane polypeptide precursor that is subsequently glycosylated and oligomerized. Most of these precursors are cleaved en route to the plasma membrane by a cellular protease furin in the late secretory pathway, generating the trimeric N-terminal receptor-binding and C-terminal fusion subunits. Here, we show that a cellular protein, MARCH8, specifically inhibits the furin-mediated cleavage of EBOV GP, HIV-1 Env, and H5N1 HA. Further analyses uncovered that MARCH8 blocked the EBOV GP glycosylation in the Golgi and inhibited its transport from the Golgi to the plasma membrane. Thus, MARCH8 has a very broad antiviral activity by specifically inactivating different viral fusion proteins.