Quantification of the Nucleus/Cytoplasm p65 intensity ratio (Nuc/Cyt p65 ratio) confirmed that the depletion of Nod1 inhibited the nuclear translocation of p65 induced during infection (Figure 1D), and therefore, that the RNAi approach was suitable to identify new proteins involved in the activation of NF-κB during S. flexneri infection of epithelial cells. The gene discussed is NFKB1; the disease is infection.