MAP3K1 and bacterial infectious disease: However, when bacterial infection takes place, PGN induces Duox production via PGRP-LC–IMD–MEKK1–p38 signaling and non-PGN stimuli activate MEKK1 through GPCR-Gaq-PLCβ-MEKK1 signaling, resulting in maximal ROS production [35] (Figure 1).