Diversification of signal identity and modus operandi of the Haemophilus influenzae PAS-less ArcB sensor kinase.

Bacteria employ two-component signal transduction systems (TCS) to sense environmental fluctuations and adjust their cellular functions. The Arc TCS is crucial for facultative anaerobes as it enables adaptation to varying respiratory conditions. The Escherichia coli ArcB detects redox changes through two cysteine amino acid residues within its PAS domain.

Identification of an ArgR-controlled promoter within the outermost region of the ISR mobile element.

Unlabelled: The transposon Tn is a prevalent composite element often detected in enteric bacteria, including those obtained from clinical samples. The Tn is flanked by two IS elements that work together in mediating transposition. IS-right (ISR) promotes transposition, while IS-left lacks a functional transposase and cannot transpose independently.

Identification of Z nucleotides as an ancient signal for two-component system activation in bacteria.

Two-component systems (TCSs) in bacteria are molecular circuits that allow the perception of and response to diverse stimuli. These signaling circuits rely on phosphoryl-group transfers between transmitter and receiver domains of sensor kinase and response regulator proteins, and regulate several cellular processes in response to internal or external cues. Phosphorylation, and thereby activation, of response regulators has been demonstrated to occur by their cognate histidine kinases but also by low molecular weight phosphodonors such as acetyl phosphate and carbamoyl phosphate.