College of Veterinary Medicine, Northwest A&F University, Yangling, Shanxi 712100, China.
College of Veterinary Medicine, Northwest A&F University, Yangling, Shanxi 712100, China.
Vet Microbiol. 2024 Jul;294:110124. doi: 10.1016/j.vetmic.2024.110124. Epub 2024 May 21.
PEDV, a single-stranded RNA virus, causes significant economic losses in the pig industry. Sin3-associated protein 18 (SAP18) is known for its role in transcriptional inhibition and RNA splicing. However, research on SAP18's involvement in PEDV infection is limited. Here, we identified an interaction between SAP18 and PEDV nonstructural protein 10 (Nsp10) using immunoprecipitation-mass spectrometry (IP-MS) and confirmed it through immunoprecipitation and laser confocal microscopy. Additionally, PEDV Nsp10 reduced SAP18 protein levels and induced its cytoplasmic accumulation. Overexpressing SAP18 suppressed PEDV replication, meanwhile its knockdown via short interfering RNA (siRNA) enhanced replication. SAP18 overexpression boosted IRF3 and NF-κB P65 phosphorylation, nuclear translocation, and IFN-β antiviral response. Furthermore, SAP18 upregulated RIG-I expression and facilitated its dephosphorylation, while SAP18 knockdown had the opposite effect. Finally, SAP18 interacted with phosphatase 1 (PP1) catalytic subunit alpha (PPP1CA), promoting PPP1CA-RIG-I interaction during PEDV infection. These findings highlight SAP18's role in activating the type I interferon pathway and inhibiting viral replication by promoting RIG-I dephosphorylation through its interaction with PPP1CA.
猪流行性腹泻病毒（PEDV）是一种单链 RNA 病毒，它会给养猪业造成巨大的经济损失。Sin3 相关蛋白 18（SAP18）以其在转录抑制和 RNA 剪接中的作用而闻名。然而，关于 SAP18 参与 PEDV 感染的研究还很有限。在这里，我们使用免疫沉淀-质谱（IP-MS）鉴定出 SAP18 与 PEDV 非结构蛋白 10（Nsp10）之间的相互作用，并通过免疫沉淀和激光共聚焦显微镜进行了验证。此外，PEDV Nsp10 降低了 SAP18 蛋白水平并诱导其细胞质积累。过表达 SAP18 抑制了 PEDV 的复制，而通过小干扰 RNA（siRNA）敲低 SAP18 则增强了复制。SAP18 的过表达促进了 IRF3 和 NF-κB P65 的磷酸化、核转位和 IFN-β 抗病毒反应。此外，SAP18 上调了 RIG-I 的表达并促进了其去磷酸化，而 SAP18 的敲低则产生相反的效果。最后，SAP18 与磷酸酶 1（PP1）的催化亚基α（PPP1CA）相互作用，在 PEDV 感染过程中促进了 PPP1CA-RIG-I 的相互作用。这些发现强调了 SAP18 通过与 PPP1CA 相互作用促进 RIG-I 去磷酸化，从而在激活 I 型干扰素通路和抑制病毒复制方面的作用。
