ArcZ targets in Escherichia coli. Green arrows indicate activation, red arrows indicate repression, and black arrows indicate either translation or activity. CyaR is an sRNA capable of repressing the translation of nadE mRNA, which encodes an enzyme involved in NAD+ biosynthesis but is also capable of repressing the translation of rpoS mRNA. ArcZ degrades CyaR via RNase E, thereby increasing the translation of nadE and the availability of NAD+ and rpoS. ArcZ enhances the translation of rpoS mRNA, which induces the Gad pathway, leading to better acid stress resistance. Additionally, ArcZ reduces the translation of mutS mRNA, both directly and indirectly, by activating the translation of rpoS, which in turn transcribes SdsR. SdsR directly represses mutS translation. ArcZ also directly represses flhDC translation and competes with the McaS sRNA, which has a common flhDC mRNA pairing site with ArcZ. McaS activates flhDC translation, while ArcZ inhibits LPS modification by repressing eptB mRNA translation. Figure was created with BioRender.com.
