RK-33 activates the integrated stress response. (A) MRC-5 cells were titrated with RK-33 after viral absorption and probed for the indicated proteins at 8 hpi. Representative western blot shown. Quantifications were made from three independent experiments. (B) Transient siRNA knockdowns were performed as in Figure 1, followed by OC43 infection and WB analysis at 8 hpi. Representative western blot shown. Quantifications were made from two independent experiments. (C) Cells were pretreated ±500 nM 2BAct for 2 h, infected with OC43 (±2BAct treatment), and treated with RK-33 ±2BAct for the remainder of the infection period (8 h). Cells were lysed and analyzed by WB. Representative western blot shown. Quantifications were made from two independent experiments. Statistical significance: (ns) not significant, (*) P ≤ 0.05, (**) P ≤ 0.01, (***) P ≤ 0.001. Tests used: one-sample t-test (A). Error bars represent mean ± SEM.
