FIGURE 3.

PERK contributes to the cell death induced by SCD1 knockdown. A and B, HeLa cells were transfected with the indicated siRNA. After 72 h, cell lysates were prepared and subjected to Western blot analysis using antibodies against IRE1α (A) and PERK (B). α-Tubulin expression was used as a loading control. siIRE1α and siPERK indicate siRNAs against IRE1α and PERK, respectively. C, cells were transfected with the indicated siRNA. At 66 h after transfection, cell viability was determined as described under “Experimental Procedures.” D, expression of CHOP mRNA was detected by quantitative real-time PCR. The expression level of each gene was normalized to expression of the GAPDH gene and is represented as -fold induction over siControl. The data represent the mean ± S.E. of three experiments. The asterisks indicate significant differences compared with siControl-transfected cells (p < 0.01). The number symbols indicate significant differences compared with siSCD1-transfected cells (p < 0.05).