Member of the two-component regulatory system BasS/BasR. BasR induces the transcription of the ugd, ais, arnBCADTEF and eptA-basRS loci, all involved in resistance to polymyxin. Represses the transcription of pmrD. Plays a role in the adaptation of the organism to the host environment, in particular to neutrophils, and therefore it plays a role in virulence as well. Homodimer. The eptA-basRS operon is positively autoregulated by BasR under high iron or aluminum concentration conditions. Phosphorylated by BasS. The activity of the BasR protein is controlled at a post-transcriptional level by the PmrD protein, under low Mg(2+) concentration conditions.