FIG 7.

PERK signaling. Cells maintained in serum and grown to 70% confluence were treated with ABC294640 (25 μM) or SKi (10 μM) for 24 h or with tunicamycin (5 μg/ml) for up to 8 h. In certain cases, cells were treated with scrambled, Degs1, SK1, or SK2 siRNA (each at a final concentration of 100 nM) for 48 h prior to treatment with SKi. Western blots probed with anti-PERK antibody show the effect of SKi, ABC294640, or tunicamycin (A), Degs1 siRNA (B), SK1 siRNA (C), or SK2 siRNA (D) on the mobility shift of PERK induced by SKi. Blots were reprobed for GAPDH or actin using anti-GAPDH or antiactin antibodies to ensure comparable protein loading. Results are representative of data from at least 3 independent experiments. Lanes C, control.