Hepatitis A virus structural protein pX interacts with ALIX and promotes the secretion of virions and foreign proteins through exosome-like vesicles
Hepatitis A virus structural protein pX interacts with ALIX and promotes the secretion of virions and foreign proteins through exosome-like vesicles
复制标题
甲型肝炎病毒结构蛋白pX与ALIX相互作用并通过外泌体样囊泡促进病毒粒子和外源蛋白的分泌
DOI：
10.1080/20013078.2020.1716513
复制
发表时间：
2020-01-01
影响因子：
16
通讯作者：
Long, Gang
中科院分区：
文献类型：
--
作者：
Jiang, Wang;Ma, Pengjuan;Long, Gang
甲型肝炎病毒（HAV）是一种典型的非包膜病毒，最近发现它主要以准包膜HAV （eHAV）的形式通过劫持宿主内体转运所需的分选复合物（ESCRT）复合物释放。与非包膜病毒粒子不同，eHAV在HAV衣壳表面含有病毒蛋白pX，作为VP1的延伸。HAV衣壳如何获得宿主包膜以及pX蛋白是否参与这一过程此前尚不清楚。在这里，我们分析了pX在外泌体样细胞外囊泡（EVs）外源蛋白分泌和eHAV形成中的作用。pX与eGFP的融合通过引导eGFP进入多泡体（multivesicular bodies, MVBs），引导eGFP进入外泌体样ev，凋亡相关基因2-相互作用蛋白X （apoptosis-linked gene 2-interacting protein X， ALIX）释放显著增强。共免疫沉淀（co-IP）证实了pX与ALIX V结构域之间的相互作用。去除了pX的c端一半，消除了eHAV的释放，降低了HAV病毒粒子与ALIX之间的相互作用。最后，仅pX的c端一半就足以通过与ALIX相互作用将eGFP加载到ev中。综上所述，pX的c端部分对eHAV的产生很重要，并且可能具有将大蛋白复合物装载到外泌体样ev中用于治疗目的的潜力。
ABSTRACT Hepatitis A virus (HAV), a classic nonenveloped virus, has recently been found to be released mainly in the form of quasi-enveloped HAV (eHAV) by hijacking host endosomal sorting complexes required for transport (ESCRT) complexes. Unlike the nonenveloped virion, eHAV contains the viral protein pX on the surface of the HAV capsid as an extension of VP1. How HAV capsids acquire the host envelope and whether the pX protein is involved in this process were previously unknown. Here, we analyse the role of pX in foreign protein secretion in exosome-like extracellular vesicles (EVs) and the formation of eHAV. Fusion of pX to eGFP guided eGFP into exosome-like EVs through directing eGFP into multivesicular bodies (MVBs), and apoptosis-linked gene 2-interacting protein X (ALIX) release was significantly enhanced. Coimmunoprecipitation (co-IP) demonstrated the interaction between pX and the ALIX V domain. Removal of the C-terminal half of pX abolished eHAV release and reduced the interaction between the HAV virion and ALIX. Finally, the C-terminal half of pX alone was sufficient for loading eGFP into EVs by interacting with ALIX. In conclusion, the C-terminal part of pX is important for eHAV production and may have potential for large protein complex loading into exosome-like EVs for therapeutic purposes.