Figure 5. The IRE1-RIDD Pathway Defines a General Rule for Innate Immune Surveillance by the ER.
(A) Wild-type MEFs or MEFs lacking IRE1α (IRE1α−/−) or RIG-I (RIG-I−/−) were intoxicated with an enzymatically inactive Shiga toxin mutant (StxE) or its B subunit alone (STxB), and IL-6 mRNA was quantified.
(B and C) T84 or Caco-2 cells pretreated or not with 4µ8C were infected with SV40 virus (B) or Anthrax-fused Diphtheria (C) for 4h and immune responses were assessed by qPCR.
(D) Wild-type macrophages or MAVS knockout macrophages pretreated or not with 4µ8C were intoxicated with toxins for 4 hr and analyzed for IL-6 by qPCR.
Data are shown as means ± SEM. PA, protective antigen; LFN, amino-terminal 255 residues of lethal factor; LFNDTA*, fusion protein composed of LFN and the inactive catalytic domain of diphtheria toxin; LFNDTA, fusion protein composed of LFN and the catalytic domain of diphtheria toxin. Other nomenclature is as in Figures 1 and 4.