Figure 8.

Regulation model. The cupD gene cluster is inversely regulated by the response regulators RcsB and PvrR. RcsB is activated by the PvrS kinase, while RcsC acts as a phosphorelay and a phosphatase. In addition to its primary target, the cupD promoter, RcsB also activates the expression of other regulatory proteins encoded on the core genome. RcsB also positively influences expression of pvrR, which downregulates production of CupD fimbriae and reduces biofilm formation. Shaded boxes: HisKA-ATPase domains; ovals: receiver domains; light grey boxes: histidine phosphotransfer (Hpt) domains; white hexagons: output domains, either helix–turn–helix (HTH) or phosphodiesterase (EAL).