Apoptosis induced by aggregation of MAP1b-LC in the DJ-1 KD SH-SY5Y was ER stress dependent. A, An increase in phosphorylated eIF-2α, an early ER stress marker, was observed at 48 hrs after transfection of Flag-MAP1b-LC (F-MAP1b-LC) in the DJ-1 KD SH-SY5Y cells. B, Dephosphorylation of eIF-2α was increased at 60 hrs after transfection of MAP1b-LC in the DJ-1 KD cells. C and D, Salubrinal, inhibitor of eIF-2α dephosphorylation, suppressed the increased apoptosis induced by MAP1b-LC in the DJ-1 KD SH-SY5Y cells (C). Statistic result showed Salubrinal inhibited the increased apoptosis in the DJ-1 KD SH-SY5Y cells induced by MAP1b-LC (D) (*, p = 0.016).