A) ADP-heptose-induced TIFA-GFP oligomerization depends on ALPK1. After siRNA transfection, HeLa cells were transfected with empty pCMV or pCMV-ALPK1 as indicated. They were then infected with wt S. flexneri (MOI 10) or treated with digitonin and ADP-heptose (10-5 M) for 30 min. As control, cells were left untreated (mock) or treated with digitonin 