TRIM28 induces the PDCoV NS6 degradation through the ubiquitin proteasome pathway.

Porcine deltacoronavirus (PDCoV) causes a significant threat to the global swine industry. The PDCoV accessory protein NS6 has the capability to antagonize type I interferon (IFN-I) production and influence viral proliferation. In this study, we discovered that tripartite motif-containing 28 (TRIM28) interacts with NS6 via its RING and coiled-coil (CC) domains, facilitating K48-linked ubiquitination of NS6, thereby leading to the degradation of NS6. Furthermore, NS6 attenuates the expression of interferon-stimulated genes (ISGs). The inhibition of the interferon (IFN) response is further intensified when the degradation of NS6 is inhibited. This study further identifies TRIM28 as an antiviral factor that restricts PDCoV replication.