|Title||Deducing receptor signaling parameters from in vivo analysis: LuxN/AI-1 quorum sensing in Vibrio harveyi.|
|Publication Type||Journal Article|
|Year of Publication||2008|
|Authors||Swem, LR, Swem, DL, Wingreen, NS, Bassler, BL|
|Date Published||2008 Aug 8|
|Keywords||4-Butyrolactone, Acyl-Butyrolactones, Amino Acid Sequence, Bacterial Proteins, Molecular Sequence Data, Mutagenesis, Site-Directed, Protein Kinases, Protein Structure, Tertiary, Quorum Sensing, Transcription Factors, Vibrio|
Quorum sensing, a process of bacterial cell-cell communication, relies on production, detection, and response to autoinducer signaling molecules. LuxN, a nine-transmembrane domain protein from Vibrio harveyi, is the founding example of membrane-bound receptors for acyl-homoserine lactone (AHL) autoinducers. We used mutagenesis and suppressor analyses to identify the AHL-binding domain of LuxN and discovered LuxN mutants that confer both decreased and increased AHL sensitivity. Our analysis of dose-response curves of multiple LuxN mutants pins these inverse phenotypes on quantifiable opposing shifts in the free-energy bias of LuxN for occupying its kinase and phosphatase states. To understand receptor activation and to characterize the pathway signaling parameters, we exploited a strong LuxN antagonist, one of fifteen small-molecule antagonists we identified. We find that quorum-sensing-mediated communication can be manipulated positively and negatively to control bacterial behavior and, more broadly, that signaling parameters can be deduced from in vivo data.