 It is studied that OA also induces PKR phosphorylation and thus, eIF2a phosphorylation.eIF2a phosphorylation then induces activation of transcription factor 4 (ATF4), which induces apoptosis and nuclear translocation, contributing to neuronal death.Glycogen Synthase Kinase Aβ (GSK-3β) is responsible for tau phosphorylation and controls several cellular functions including apoptosis.