Silencing PERK delays apoptotic cell death at TG treatment. (A) Immunoblot results of key regulatory components. HEK293T cells were treated with 10 µM TG for 2 h without/with using PERK siRNA. The expression of the crucial autophagy (LC3II, ULK-555-P), apoptosis (cleaved PARP), PERK (PERK-T, eiF2α-P, CHOP) and IRE-1 (JNK-P, XBP1) markers followed in 30 min intervals by immunoblotting. All the markers except XBP1 were done by Western blot, while splicing of XBP1 was followed by RT-PCR. GAPDH was used as the housekeeping gene. (B) Densitometry data of immunoblotting. The intensity of PERK, LC3II, cleaved PARP, CHOP is normalized for GAPDH, eiF2α-P is normalized for total level of eiF2α, ULK-555-P is normalized for total level of ULK-T, JNK-P is normalized for total level of JNK and spliced XBP1 level is normalized for total level of unspliced XBP1. Three parallel experiments were carried out (error bars represent standard deviation, asterisks indicate statistically significant difference: ** p < 0.01); ns: not significant.