CemR atypical response regulator impacts energy conversion in Campylobacteria
Campylobacter jejuni and Arcobacter butzleri are microaerobic food-borne human gastrointestinal pathogens that mainly cause diarrheal disease. These related species of the Campylobacteria class face variable atmospheric environments during infection and transmission, ranging from nearly anaerobic to aerobic conditions. Consequently, their lifestyles require that both pathogens need to adjust their metabolism and respiration to the changing oxygen concentrations of the colonization sites. Our studies revealed that C. jejuni and A. butzleri lacking a Campylobacteria-specific regulatory protein, C. jejuni Cj1608 or a homologue A. butzleri Abu0127, are unable to reprogram tricarboxylic acid cycle or respiration pathways, respectively, to produce ATP efficiently and, in consequence, adjust growth to changing oxygen supply. We propose that these Campylobacterial energy and metabolism regulators (CemR) are long-sought transcription factors controlling the metabolic shift related to oxygen availability, essential for these bacterias survival and adaptation to the niches they inhabit.