EIF2AK3 and viral encephalitis: For example, the Japanese encephalitis virus induces apoptosis and encephalitis by activating the PERK pathway, whereas porcine circovirus type 2 induces ORF3-independent apoptosis by activating ER stress and the PERK-activating transcription factor 4 (ATF4)-CHOP axis (20, 21, 49).