FIGURE 8.

Regulatory model of methylcitrate pathway by RegX3 in Mycobacteria. Phosphate-responsive RegX3 and propionate-responsive PrpR competitively regulate the transcription of prpDBC operon involved in methylcitrate pathway (MCS, MCD, and MCL), which play an important role in metabolism of cholesterol and fatty acids as the main nutrient sources of mycobacteria during infection. It was suggested that RegX3 contributed to establish a direct association between phosphate and carbon metabolisms, and also modulate the C-P balance in mycobacteria. The wave lines indicate transmembrane transport. The fold line with arrow indicates signal stimulus. The red lines with arrows indicate positive transcriptional regulation while the light blue lines with arrows indicate compound synthesis process.