Figure 3. Genome-wide roles of the GadEWX regulons in E. coli.

Regulation of (a) GadEWX regulatory circuits and (b) core genes in the glutamate-dependent acid resistance (GDAR) system. Closed and open circles represent whether target genes are bound by TF or not. Triangle, inverted triangle, and dash indicate whether the expression levels of target genes are activated, repressed, or not changed upon TF knockout. Red, GadE; Green, GadW; Blue, GadX. (c) Schematic diagram for the reconstructed GadEWX regulatory motif for acidic pH homeostasis. The GadEWX repressed proton-influx system (T_I) and proton-generating metabolic enzymes (M_G) while activated proton-consuming metabolic enzymes (M_C). We were not able to observe regulation of proton-efflux system (T_E) by GadEWX. IM, inner membrane; OM, outer membrane. (d) GadEWX regulatory networks regulate diverse cellular functions. Arrows with dotted lines indicate that the regulation is not observed in this study.