ATF5 and infection: In the invertebrate model organism C. elegans, the UPRmt protects the host during pathogen infection by promoting mitochondrial recovery and the induction of innate immunity-related antimicrobial effectors.16,20,22,23 Here, we find that the mammalian UPRmt regulator ATF5 functions similarly in protecting the host during enteric pathogen infection, except that it does so by a mechanism involving the maintenance of intestinal barrier function.