Plays a key role in regulating expression of enzymes involved in the catabolism of short chain fatty acids (SCFA) via both the glyoxylate (acetyl degradation route) and the methylcitrate cycle (propionate degradation route) (PubMed:22916289, PubMed:24705740). Required for intracellular growth in macrophages and for the assimilation of cholesterol-derived propionate (PubMed:22365605). PrpR acts as a transcriptional activator of prpDC and icl genes when propionate is the main carbon source, and as a ramB repressor (PubMed:22916289). During growth on propionate, PrpR also acts as a transcriptional repressor of dnaA, which encodes the DnaA initiator protein responsible for initiating chromosomal replication (PubMed:24705740). It is possibly involved in the regulation of genes responsible for controlling cholesterol utilization (PubMed:22365605). Organic acid metabolism; propanoate degradation. Steroid metabolism; cholesterol metabolism. By propionate. Cells lacking this gene are unable to grow using either propionate or cholesterol as a primary carbon source and the transcript levels of both prpD and prpC are dramatically reduced regardless of carbon source. When the mutant grows on medium containing glucose or acetate as a sole carbon source, there is no significant difference in growth compared to the wild-type. Belongs to the short-chain fatty acyl-CoA assimilation regulator (ScfR) family.