The PERK-eIF2α Pathway of the Unfolded Protein Response Inhibits White Spot Syndrome Virus Infection by Attenuating Global Protein Translation.

As obligate intracellular pathogens, viruses rely on the endoplasmic reticulum (ER) of host cells for viral protein synthesis and processing, leading to increased ER loading, which in turn triggers ER stress and activates the unfolded protein response (UPR). And this process is intricately linked to both viral infection and the host's immune response. White spot syndrome virus (WSSV) is one of the most detrimental viral pathogens affecting farmed crustaceans such as shrimp and crayfish, but the interaction between WSSV-induced ER stress and viral infection has not been comprehensively investigated. Here, we demonstrated that WSSV infection activated all three UPR pathways, including IRE1 pathway, ATF6 pathway and PERK-eIF2α pathway in crayfish hematopoietic tissue cells. In contrast to the promoted WSSV infection by IRE1 pathway and ATF6 pathway, the activated PERK-eIF2α pathway exhibited an inhibitory effect on viral infection, which was achieved via attenuation of global protein translation of host cells mediated by phosphorylation of eIF2α. Whereas, the continuous expression of WSSV proteins appeared to bypass this translational repression. Collectively, these results emphasized the key role of the PERK-eIF2α pathway, activated by WSSV-induced ER stress, in regulating viral infection, which might constitute an important aspect of the host cell's immune response to viral infection.