Figure 3.

PAT induces p62-mediated cytoprotective ER stress. (a) UPR induced by PAT in HaCaT cells. The cells were treated with various concentrations of PAT for 24 h and then ER stress associated markers were analyzed by western blotting. (b) Effects of IRE1α or PERK inactivation by RNAi on PAT-induced apoptosis. The cells were transfected with 60 nmol/l of IRE1α or PERK siRNA using siPORT NeoFX transfection agent. At 24 h post transfection, the cells were treated with 7 μM PAT for 24 h and apoptosis induction was assessed by a Cell Death Detection ELISA kit (left) and Annexin V staining (right). (c) Effects of p62 inhibition by RNAi on PAT-induced activation of UPR. The cells were transfected with 60 nmol/l of p62 siRNA using siPORT NeoFX transfection agent. At 24 h post transfection, the cells were treated with 7 μM PAT for 24 h. IRE1α and eIF2α phosphorylation were assessed by western blotting