Stimulation of ISG expression by LntA during infection is impaired by mutation of the K180/K181 dilysine motif. Innate immune gene expression was quantified by RT-qPCR in noninfected LoVo cells (NI) or cells infected for 18 h with L. monocytogenes lntA∅, lntAWT, lntAK180R/K181R, or lntAK180D/K181D (left). Induction of the expression of interleukin 8 (IL-8), IFI6, and IFITM1 by L. monocytogenes lntA∅ and L. monocytogenes lntAWT, compared to uninfected cells (right). LntA-dependent induction of ISGs, monitored by normalization to cells infected with L. monocytogenes lntA∅. Error bars indicate standard deviations. The reference gene for normalization was YWHAZ; GAPDH was a control invariant gene. Statistical analysis was performed using analysis of variance (ANOVA) followed by the Tukey-Kramer posttest. ns, nonsignificant; ***, P < 0.001.