FIGURE 1.

ER stress-induced expression of ER- and mitochondria-related factors. INS-1 cells were treated with either vehicle (DMSO) or thapsigargin (1 μm) and incubated for up to 24 h. At various times, the cells were harvested and cytosol and mitochondrial fractions were prepared. Proteins in each fraction were then resolved by SDS-PAGE and processed for immunoblotting analyses. Tubulin or complex IV immunoreactivity was used as control. A, ER factors. B, mitochondrial factors. C, caspase-3. Immunoreactive bands were visualized by ECL. D, quantitation of band intensities. Ratios of factor to control band intensity from a representative blot are presented (Vector, empty vector-transfected and OE, iPLA₂β-overexpressing INS-1 cells). Each analysis was done three times.