Differential maturation and subcellular localization of severe acute respiratory syndrome coronavirus surface proteins S, M and E
Differential maturation and subcellular localization of severe acute respiratory syndrome coronavirus surface proteins S, M and E
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DOI：
10.1099/vir.0.80671-0
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发表时间：
2005-05-01
影响因子：
3.8
通讯作者：
Altmeyer, R
中科院分区：
文献类型：
--
作者：
Nal, B;Chan, CM;Altmeyer, R
病毒结构蛋白的翻译后修饰和正确的亚细胞定位是包膜病毒组装和出芽的先决条件。冠状病毒，如严重急性呼吸综合征相关病毒（SARS-CoV），从内质网-高尔基体中间室出芽。在这项研究中，SARS-CoV表面蛋白S，M和E的亚细胞分布和成熟的分析，通过使用C-末端标记的蛋白。早在进入内质网后30分钟，高甘露糖基化的S在高尔基体中获得复杂的N-聚糖之前组装成三聚体。像S一样，M获得高甘露糖N-聚糖，其随后在高尔基体中被修饰成复杂的N-聚糖。N-糖基化谱和M蛋白上O-糖基化的缺乏将SARS-CoV与先前描述的组1和组3冠状病毒相关联。免疫荧光分析表明，S被检测到在几个隔室沿着从内质网到质膜的分泌途径，而M主要定位在高尔基体，在那里它积累，并在运输囊泡。E蛋白未被糖基化。脉冲追踪标记和共聚焦显微镜在蛋白质翻译抑制剂放线菌酮的存在下发现，E蛋白有一个短的半衰期为30分钟。E蛋白被发现在明亮的核周补丁共定位与内质网标记。总之，SARS-CoV表面蛋白S，M和E显示差异的亚细胞定位时，单独表达，表明额外的细胞或病毒因子可能需要协调贩运到内质网高尔基体中间隔室的病毒组装位点。
Post-translational modifications and correct subcellular localization of viral structural proteins are prerequisites for assembly and budding of enveloped viruses. Coronaviruses, like the severe acute respiratory syndrome-associated virus (SARS-CoV), bud from the endoplasmic reticulum-Golgi intermediate compartment. In this study, the subcellular distribution and maturation of SARS-CoV surface proteins S, M and E were analysed by using C-terminally tagged proteins. As early as 30 min post-entry into the endoplasmic reticulum, high-mannosylated S assembles into trimers prior to acquisition of complex N-glycans in the Golgi. Like S, M acquires high-mannose N-glycans that are subsequently modified into complex N-glycans in the Golgi. The N-glycosylation profile and the absence of O-glycosylation on M protein relate SARS-CoV to the previously described group 1 and 3 coronaviruses. Immunofluorescence analysis shows that S is detected in several compartments along the secretory pathway from the endoplasmic reticulum to the plasma membrane while M predominantly localizes in the Golgi, where it accumulates, and in trafficking vesicles. The E protein is not glycosylated. Pulse-chase labelling and confocal microscopy in the presence of protein translation inhibitor cycloheximide revealed that the E protein has a short half-life of 30 min. E protein is found in bright perinuclear patches colocalizing with endoplasmic reticulum markers. In conclusion, SARS-CoV surface proteins S, M and E show differential subcellular localizations when expressed alone suggesting that additional cellular or viral factors might be required for coordinated trafficking to the virus assembly site in the endoplasmic reticulum-Golgi intermediate compartment.