EHEC responds to microbiota-derived metabolites to activate complex regulatory cascades. EHEC senses ethanolamine, butyrate, and succinate to activate virulence gene expression, whereas the two-component system FusKR represses LEE expression in response to fucose. Ethanolamine is sensed through EutR as well as an unidentified ethanolamine sensor; butyrate is sensed through the transcription factor Lrp; succinate is sensed by Cra. Black lines indicate direct interaction, and grey hashed arrows indicate indirect regulation. For details, refer to main text.