Plays an important role in the regulation of the production of the virulence factor exotoxin A (toxA), via positive regulation of the transcription of the toxA gene (PubMed:8843437, PubMed:10696480, PubMed:22844393). Acts by binding directly to the toxA promoter region (PubMed:22844393). Besides toxA, PtxR modulates the expression of genes that code for the QS-controlled virulence factors (PubMed:16803594). It negatively regulates the expression of the rhamnolipid and pyocyanine genes, through the autoinducer synthase RhlI, and the PQS synthesis operon pqsABCDE, while it positively regulates the expression of lasB through the autoinducer synthase LasI (PubMed:16803594). Also positively regulates the expression of the exotoxin A regulatory protein (toxR or regA) (PubMed:8843437, PubMed:10696480). In addition, is involved in the positive regulation of glucose metabolism via the regulation of the expression of the kgu and gad operons (PubMed:22844393, PubMed:24019239). Acts by binding directly to the promoter region of the kgu and gad operons (PubMed:22844393, PubMed:24019239). Negatively regulated by PtxS, which interacts with PtxR and prevents its activity. Monomer in solution (PubMed:24019239). May dimerize on binding to DNA (PubMed:24019239). Interacts with PtxS in the absence of 2-ketogluconate (PubMed:22844393, PubMed:24019239). Binding of the 2-ketogluconate effector to PtxS causes PtxS/PtxR complex dissociation (PubMed:22844393, PubMed:24019239). The level of expression at different time points of growth is generally low (PubMed:16000716, PubMed:16699585). Expression increases when P.aeruginosa is grown in static cultures and under reduced levels of environmental oxygen, two conditions that resemble the environment within the lung alveoli of cystic fibrosis patients (PubMed:16000716). The ptxR upstream region contains two independent transcription initiation sites (T1 and T2), and potential binding sites for multiple regulators (PubMed:9852033, PubMed:16699585, PubMed:18048935, PubMed:18227247). Under aerobic conditions in iron-deficient medium, ptxR expression follows a biphasic curve that involves the P1 promoter only (PubMed:16699585). Iron eliminates the second peak of expression but does not affect expression from the P2 promoter (PubMed:16699585). Under microaerobic conditions, iron represses expression from subclones that carry P1 alone or P2 alone at both early and late stages of growth (PubMed:16699585). Under anaerobic conditions, expression increases considerably (PubMed:16699585). P1 is recognized by sigma-70 (PubMed:16699585). Regulated by the iron-starvation sigma factor PvdS under reduced levels of oxygen (PubMed:18048935). Vfr may be required for P2 expression throughout the growth cycle in iron-deficient medium (PubMed:18227247). Mutant produces lower levels of exotoxin A (PubMed:8843437). Mutant also produces significantly more pyocyanine than its parent strain (PubMed:16803594). Belongs to the LysR transcriptional regulatory family.