BST2 suppresses porcine epidemic diarrhea virus replication by targeting and degrading virus nucleocapsid protein with selective autophagy
BST2 suppresses porcine epidemic diarrhea virus replication by targeting and degrading virus nucleocapsid protein with selective autophagy
复制标题
BST2 通过选择性自噬靶向和降解病毒核衣壳蛋白来抑制猪流行性腹泻病毒复制
DOI：
10.1080/15548627.2019.1707487
复制
发表时间：
2019-12-29
期刊：
影响因子：
13.3
通讯作者：
Tong, Guangzhi
中科院分区：
文献类型：
--
作者：
Kong, Ning;Shan, Tongling;Tong, Guangzhi
干扰素诱导的BST 2（骨髓基质细胞抗原2）通过将包膜病毒粒子束缚在细胞表面以限制病毒释放和诱导NF κ B依赖性抗病毒免疫应答来抑制病毒复制。然而，BST 2使用选择性自噬途径来抑制病毒复制的机制知之甚少。在这项研究中，我们发现，在猪流行性腹泻病毒（PEDV）感染Vero细胞的IRF 1针对其启动子的BST 2的表达显着增加。我们还表明BST 2通过结合和降解PEDV编码的核衣壳（N）蛋白来抑制PEDV复制。N蛋白的下调被大自噬/自噬抑制剂阻断，但不被蛋白酶体抑制剂阻断，这意味着N蛋白通过选择性自噬途径降解。BST 2和N蛋白均与E3泛素连接酶MARCHF 8/MARCH 8和货物受体CALCOCO 2/NDP 52相互作用，并且N蛋白的泛素化是BST 2-MARCHF 8轴介导的N降解所必需的。用小干扰RNA敲低MARCHF 8或ATG 5阻断了选择性自噬途径，拯救了293 T细胞中PEDV N的蛋白丰度，并阻止了BST 2对Vero细胞中PEDV复制的抑制。总之，我们的数据证明了BST 2介导的病毒限制的新机制，其中BST 2招募MARCHF 8来催化PEDV N蛋白的泛素化。泛素化的N蛋白随后被CALCOCO 2/NDP 52识别，CALCOCO 2/NDP 52通过选择性自噬途径将其递送至自溶体进行降解。
Interferon-induced BST2 (bone marrow stromal cell antigen 2) inhibits viral replication by tethering enveloped virions to the cell surface to restrict viral release and by inducing the NFKB-dependent antiviral immune response. However, the mechanism by which BST2 uses the selective autophagy pathway to inhibit viral replication is poorly understood. In this study, we showed that BST2 expression was significantly increased during porcine epidemic diarrhea virus (PEDV) infection of Vero cells by IRF1 targeting its promoter. We also showed that BST2 suppressed PEDV replication by binding and degrading the PEDV-encoded nucleocapsid (N) protein. The downregulation of N protein was blocked by macroautophagy/autophagy inhibitors but not a proteasome inhibitor, implying that the N protein was degraded via the selective autophagy pathway. Both the BST2 and N protein interacted with the E3 ubiquitin ligase MARCHF8/MARCH8 and the cargo receptor CALCOCO2/NDP52, and the ubiquitination of N protein was necessary for the degradation of N mediated by the BST2-MARCHF8 axis. The knockdown of MARCHF8 or ATG5 with small interfering RNAs blocked the selective autophagy pathway, rescued the protein abundance of PEDV N in 293T cells, and prevented the inhibition of PEDV replication by BST2 in Vero cells. Together, our data demonstrate the novel mechanism of BST2-mediated virus restriction, in which BST2 recruits MARCHF8 to catalyze the ubiquitination of the PEDV N protein. The ubiquitinated N protein is then recognized by CALCOCO2/NDP52, which delivers it to autolysosome for degradation through the selective autophagy pathway.