College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China.
College of Pharmaceutical Engineering, Henan University of Animal Husbandry and Economy, Zhengzhou 450046, China.
Viruses. 2018 Jun 5;10(6):305. doi: 10.3390/v10060305.
Classical swine fever, caused by classical swine fever virus (CSFV), is a highly contagious and high-mortality viral disease, causing huge economic losses in the swine industry worldwide. CSFV non-structural protein 3 (NS3), a multifunctional protein, plays crucial roles in viral replication. However, how NS3 exactly exerts these functions is currently unknown. Here, we identified tumor necrosis factor receptor-associated factor 5 (TRAF5) as a novel binding partner of the NS3 protein via yeast two-hybrid, co-immunoprecipitation and glutathione -transferase pull-down assays. Furthermore, we observed that TRAF5 promoted CSFV replication in porcine alveolar macrophages (PAMs). Additionally, CSFV infection or NS3 expression upregulated TRAF5 expression, implying that CSFV may exploit TRAF5 via NS3 for better growth. Moreover, CSFV infection and TRAF5 expression activated p38 mitogen activated protein kinase (MAPK) activity, and inhibition of p38 MAPK activation by the SB203580 inhibitor suppressed CSFV replication. Notably, TRAF5 overexpression did not promote CSFV replication following inhibition of p38 MAPK activation. Our findings reveal that TRAF5 promotes CSFV replication via p38 MAPK activation. This work provides a novel insight into the role of TRAF5 in CSFV replication capacity.
古典猪瘟是由古典猪瘟病毒（CSFV）引起的一种高度传染性和高死亡率的病毒性疾病，给全球养猪业造成了巨大的经济损失。CSFV 的非结构蛋白 3（NS3）是一种多功能蛋白，在病毒复制中发挥着关键作用。然而，NS3 如何确切地发挥这些功能目前尚不清楚。在这里，我们通过酵母双杂交、共免疫沉淀和谷胱甘肽转移酶 pull-down 实验鉴定了肿瘤坏死因子受体相关因子 5（TRAF5）是 NS3 蛋白的一个新的结合伴侣。此外，我们观察到 TRAF5 促进了猪肺泡巨噬细胞（PAMs）中的 CSFV 复制。此外，CSFV 感染或 NS3 表达上调了 TRAF5 的表达，这表明 CSFV 可能通过 NS3 利用 TRAF5 以更好地生长。此外，CSFV 感染和 TRAF5 表达激活了 p38 丝裂原活化蛋白激酶（MAPK）活性，而 p38 MAPK 激活的抑制剂 SB203580 抑制了 CSFV 的复制。值得注意的是，在抑制 p38 MAPK 激活后，TRAF5 的过表达并没有促进 CSFV 的复制。我们的研究结果表明，TRAF5 通过 p38 MAPK 激活促进 CSFV 的复制。这项工作为 TRAF5 在 CSFV 复制能力中的作用提供了新的见解。
