Pirk-like acts as an essential negative regulator of the IMD pathway.

(A) Immunostaining of WT and Pirk-like-/- mosquito fat bodies that were stimulated with PBS or E. cloacae at 12 h PBM and then dissected to measure PGRP-LC and Rel2 expressions at 24 h post infection. Scale bar: 20 μm. (B and C) Quantification of relative fluorescence intensity of cells shown in (A). Quantification showing mean ± SEM from three independent experiments. (D) Heatmap of the 28 shared IMRGs. They show the highest abundance among bacteria-infected Pirk-like-/- mosquitoes (Pirk-like-/-_Ec) and the lowest among bacteria-infected WT mosquitoes (WT_Ec), with an intermediate level of abundance in non-infected Pirk-like-/- mosquitoes (Pirk-like-/-_PBS). Non-infected WT mosquitoes (WT_PBS) were used as control. (E) Survival rate of Pirk-like-/-, Pirk-like+/- and WT female mosquitoes after E. cloacae infection. n = 3 cohorts (total 90 mosquitoes). (F) Survival rate of Pirk-like-/- and WT female mosquitoes after infection. Mosquitoes were fed with 1 mM ThT during the PBM phase. n = 3 cohorts (total 90 mosquitoes).