Fig. 1: Mechanism of environmental phosphate sensing by the PstSCAB-PhoRB pathway. | Communications Biology

Fig. 1: Mechanism of environmental phosphate sensing by the PstSCAB-PhoRB pathway.

From: The cytoplasmic phosphate level has a central regulatory role in the phosphate starvation response of Caulobacter crescentus

Fig. 1

A Control of the activation state of the response regulator PhoB through the transport activity of the PstSCAB high-affinity phosphate transport system, as described for C. crescentus22,25. At high environmental phosphate concentrations, the PstSCAB system is predominantly in a substrate-bound state, which prevents the phosphorylation of the histidine kinase PhoR and thus the phosphorylation of the regulator PhoB. At low phosphate concentrations, the vacant form of the PstSCAB system activates PhoR, which then phosphorylates PhoB, thereby promoting its interaction with specific binding sites (PHO boxes) in target promoter regions. PhoU is a regulatory protein that may control the transport activity of the PstSCAB system21,22. B Organization of the phoR, pstCAB-phoUB and pstS genes and activating effect of phosphorylated PhoB on pstSCAB-phoUB and pstS expression.

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