The viral BCL2 protein BHRF1 of Epstein–Barr virus promotes AIM2 inflammasome activation to facilitate lytic replication

The absent in melanoma 2 (AIM2) protein recognizes viral and naked dsDNA and recruit apoptosis-associated speck-like protein containing CARD (ASC) to initiate inflammasome activation; however, the subversion of AIM2 activation by Epstein-Barr virus (EBV) infection remains unknown. Here, we reveal that the EBV-encoded viral BCL2 protein BHRF1 promotes AIM2 inflammasome activation. The BHRF1 C-terminal domain binds to AIM2 HIN domain and directly promotes dsDNA recognition and AIM2-ASC interaction, consequently cooperates with viral dsDNA to enable inflammasome activation. The single-site mutations R162A and F164A in BHRF1 and E186A in AIM2 abolish their interaction and AIM2 inflammasome activation. BHRF1 recruits AIM2 inflammasome to the mitochondrial compartment and facilitates EBV lytic replication through KAP1 and GSDMD cleavage. BHRF1 deficiency strongly decreases AIM2 inflammasome activation and EBV lytic replication, and reintroduction of wild-type BHRF1 but not the BHRF1 R162A or F164A mutant restores these functions. These results suggest that BHRF1 protein directly promotes the AIM2 inflammasome activation in the mitochondrial compartment to facilitate lytic replication.