Loss of ribosomal protein RPL22 restricts African swine fever virus replication by inducing PERK-dependent ER stress.

African swine fever virus (ASFV) is a large DNA virus that causes highly lethal disease in domestic pigs and wild boars, posing a significant threat to the global swine industry. The development of effective antivirals and vaccines is hindered by the complex structure of the virus and its sophisticated manipulation of host cellular processes. The inner envelope protein p54 is essential for multiple stages of the viral life cycle, including attachment, entry, and replication. In this study, we employed TurboID-based proximity labeling to systematically map the host protein interactome of ASFV p54. Our screen identified 257 potential host interacting partners. Among these, the interaction between p54 and the 60S ribosomal protein L22 (RPL22) was validated by co-immunoprecipitation and confocal microscopy. Functional studies using an RPL22-knockout (RPL22-KO) cell line revealed that RPL22 serves as a regulatory host factor for ASFV infection. Mechanistically, the loss of RPL22 significantly inhibited ASFV replication through the activation of the PERK signaling pathway. This finding was further substantiated by pharmacological intervention; activation of the ERS/PERK pathway using thapsigargin (Tg) or CCT020312 suppressed viral replication, whereas its inhibition with 4-phenylbutyric acid (4-PBA) or AMG-PERK 44 promoted replication. In conclusion, this study presents the first systematic interactome of ASFV p54 and reveals a novel mechanism by which the host factor RPL22 modulates ASFV replication via the ERS-PERK pathway. These findings offer new insights into ASFV-host interactions and identify the ERS pathway as a promising therapeutic target for the development of anti-ASFV strategies.