Porcine epidemic diarrhea virus (PEDV) belongs to the Alphacoronavirus genus in the Coronaviridae family. Similar to other coronaviruses, PEDV encodes two papain-like proteases. Papain-like protease (PLP)2 has been proposed to play a key role in antagonizing host innate immunity. However, the function of PLP1 remains unclear. In this study, we found that overexpression of PLP1 significantly promoted PEDV replication and inhibited production of interferon-β. Immunoprecipitation and mass spectrometry were used to identify cellular interaction partners of PLP1. Host cell poly(C) binding protein 2 (PCBP2) was determined to bind and interact with PLP1. Both endogenous and overexpressed PCBP2 co-localized with PLP1 in the cytoplasm. Overexpression of PLP1 upregulated expression of PCBP2. Furthermore, overexpression of PCBP2 promoted PEDV replication. Silencing of endogenous PCBP2 using small interfering RNAs attenuated PEDV replication. Taken together, these data demonstrated that PLP1 negatively regulated the production of type 1 interferon by interacting with PCBP2 and promoted PEDV replication.

猪流行性腹泻病毒（PEDV）属于Alphacoronavirus冠状病毒科的属。与其他冠状病毒相似，PEDV编码两种木瓜蛋白酶样蛋白酶。已经提出木瓜蛋白酶样蛋白酶（PLP）2在拮抗宿主先天免疫中起关键作用。但是，PLP1的功能仍不清楚。在这项研究中，我们发现PLP1的过表达显着促进PEDV复制并抑制β-干扰素的产生。免疫沉淀和质谱用于鉴定PLP1的细胞相互作用伙伴。确定宿主细胞poly（C）结合蛋白2（PCBP2）与PLP1结合并相互作用。内源性和过表达的PCBP2与PLP1共同定位在细胞质中。PLP1的过表达上调了PCBP2的表达。此外，PCBP2的过表达促进了PEDV复制。使用小的干扰RNA沉默内源性PCBP2会减弱PEDV复制。总之，这些数据表明PLP1通过与PCBP2相互作用负调节了1型干扰素的产生，并促进了PEDV复制。