FIGURE 7.

Unfolded protein response is up-regulated in cells expressing the IL23Rα G149R variant. A, HEK293 cells stably expressing IL23Rα and its variants were harvested, and cell lysates were electrophoresed on SDS-PAGE followed by Western blot. Antibodies specific to ER stress and unfolded protein response markers indicate that BiP abundance is higher in IL23Rα G149R compared with the common variant, suggesting that IL23Rα G149R is retained in the ER. BiP abundance could also be induced in HEK293 cells expressing IL23Rα when these cells are treated with tunicamycin (1 μg/ml) for 5 h. B, the viability of cells expressing IL23Rα variants is not affected. HEK293 cells stably expressing IL23Rα and variants were plated in 96-well plate (20,000 cells) in triplicate. The next day the cells were assayed for levels of mitochondrial dehydrogenase activity by using MTT (64). Data and error bars represent the S.D. from three independent experiments.