LsrR transcriptional repressor (LsrR)

LsrR (LuxS-regulated repressor) is a key transcriptional regulator in the SorC/DeoR family that controls the uptake and processing of Autoinducer-2 (AI-2), a universal signal molecule for interspecies quorum sensing in bacteria such as Escherichia coli and Salmonella enterica [UniProt P0A9I0; PMID: 17233824]. In its apo-form, LsrR binds to the promoter of the lsr operon, repressing genes responsible for AI-2 transport; upon the accumulation of intracellular phospho-AI-2, the repressor dissociates, triggering a positive feedback loop of AI-2 uptake [PMID: 19321645]. This regulatory circuit is crucial for the coordination of group behaviors, including biofilm formation and the expression of virulence factors necessary for host colonization and infection [PMID: 25605310]. Because LsrR modulates pathogenicity without directly affecting bacterial viability, it is considered a high-priority target for anti-virulence therapies designed to bypass traditional antibiotic resistance mechanisms [PMID: 30256134]. Small molecules, such as AI-2 analogs and certain flavonoids like quercetin, have been shown to interact with LsrR or its signaling pathway to disrupt bacterial communication and attenuate infection [PMID: 23838290].

Other names

LuxS-regulated transcriptional repressorAutoinducer-2 repressorAI-2 repressorDeoR-family transcriptional regulator LsrR

Modulation of LsrR DNA-binding affinity through competitive binding or allosteric inhibition, leading to the premature or inhibited induction of the lsr operon and disruption of quorum sensing-mediated virulence.