 Another study demonstrated that tunicamycin or Aβ treatment can induce PKR activation in human neuroblastoma cells and can trigger GSK3β activation, as well as tau phosphorylation.They found that in AD brains, both activated PKR and GSK3β co-localize with phosphorylated tau in neurons.In SH-SY5Y cell cultures, tunicamycin and Aβ(1-42) activate PKR, which then can modulate GSK-3β activation and induce tau phosphorylation, apoptosis.