BvgAS
BvgAS is a two-component regulatory system found in Bordetella species, most notably Bordetella pertussis, that orchestrates the expression of virulence factors. It consists of BvgS, a sensor histidine kinase located in the inner membrane, and BvgA, a cytoplasmic response regulator. BvgS autophosphorylates in response to environmental cues and transfers the phosphate to BvgA. Phosphorylated BvgA binds targeted promoters to activate transcription of a virulence regulon, while in other states its activity is reduced, shifting the bacteria toward a less virulent phenotype.
The BvgA-regulated virulence genes include major adhesins and toxins such as pertussis toxin genes, adenylate cyclase
Environmental signals modulate BvgAS activity. Conditions such as high concentrations of divalent cations (for example Mg2+
Structurally, BvgS contains periplasmic sensing domains and cytoplasmic kinase and receiver regions, whereas BvgA possesses a