Although these studies showed a protective role of PERK/ATF4, a follow-up study from the same group reported that CHOP and ATF4 mediate the transcription of Trib3 (tribbles pseudo kinase 3), a protein with pro-apoptotic function that is highly activated in PC12 cells under 6-OHDA in an in vitro model of PD [162]. Here, ATF4 is linked to Parkinson disease.