Transcription regulator that plays a critical role in virulence by positively regulating the expression of multiple quorum sensing (QS)-regulated virulence factors, genes involved in protein secretion, translation, response to oxidative stress and the phnAB operon (PubMed:11724939, PubMed:27678057, PubMed:17083468). At the stationary phase, negatively autoregulates its function through cleavage and translocation to the extracellular space (PubMed:11724939). Both 3,4-dihydroxy-2-heptylquinoline (PQS) and its precursor 4-hydroxy-2-heptylquinoline (HHQ) function as ligands and promote MvfR DNA-binding activity leading to transcriptional activation. Forms homooligomers. At stationary phase, gets cleaved and subsequently released in the extracellular space where its transcriptional activity is inhibited. Belongs to the LysR transcriptional regulatory family.