Signal production and detection specificity in Vibrio CqsA/CqsS quorum‐sensing systems

Abstract

SummaryQuorum sensing is a process of bacterial cell–cell communication that enables populations of cells to carry out behaviours in unison. Quorum sensing involves detection of the density-dependent accumulation of extracellular signal molecules called autoinducers that elicit population-wide changes in gene expression. In Vibrio species, CqsS is a membrane-bound histidine kinase that acts as the receptor for the CAI-1 autoinducer which is produced by the CqsA synthase. In Vibrio cholerae, CAI-1 is (S)-3-hydroxytridecan-4-one. The C170 residue of V. cholerae CqsS specifies a preference for a ligand with a 10-carbon tail length. However, a phenylalanine is present at this position in Vibrio harveyi CqsS and other homologues, suggesting that a shorter CAI-1-like molecule functions as the signal. To investigate this, we purified the V. harveyi CqsS ligand, and determined that it is (Z)-3-aminoundec-2-en-4-one (Ea-C8-CAI-1) carrying an 8-carbon tail. The V. harveyi CqsA/CqsS system is exquisitely selective for production and detection of this ligand, while the V. cholerae CqsA/CqsS counterparts show relaxed specificity in both production and detection. We isolated CqsS mutants in each species that display reversed specificity for ligands. Our analysis provides insight into how fidelity is maintained in signal transduction systems.

Microbiome shifts and the inhibition of quorum sensing by Black Band Disease cyanobacteria

“…Although vibrios were detected at moderately low levels in both healthy coral mucus and in the black band, vibrios are readily cultivable from both sample types and have QS activity through both the AHL-based autoinducer 1 system and the furanosyl borate diester-based autoinducer 2 system (Tait et al, 2010;Alagely et al, 2011a;Golberg et al, 2011Golberg et al, , 2013Zimmer et al, 2014). In addition to AHLs and AI-2, vibrios also produce hydroxyketone CAI-1 signals (Henke and Bassler, 2004;Ng et al, 2011;Wei et al, 2012), and with this study we demonstrate that coral vibrios also produce CAI-1-like activities. Furthermore, this CqsS/CAI-1 QS system appears vulnerable to manipulation by lyngbic acid, a cyanobacterial secondary metabolite.…”

Caenorhabditis elegans Recognizes a Bacterial Quorum-sensing Signal Molecule through the AWCON Neuron

“…Specifically, we found the order of chemotactic preference to be: CAI-1 ϭ (C9)-CAI-1 Ͼ (C8)-CAI-1 ϭ (C11)-CAI-1. Interestingly, this order of preference for tail length exactly parallels the CqsS receptor preference (9,28,33). To assess the generality of this response to other bacterial signaling molecules containing fatty acid tails, we examined the responses of C. elegans to a series of acylated homoserine lactone AIs.…”

“…The information contained in the AIs is funneled into a phosphorelay signaling cascade that controls virulence, biofilm formation, and other traits (3,12,13). CAI-1 is the dominant signal in V. cholerae (7)(8)(9)(10).…”

Meddling Vibrio cholerae Murmurs: A Neoteric Advancement in Cholera Research

“…V. cholerae QS response is being elicited on sensing the signals, amino-CAI-1 or CAI- Fig. 2 Vibrio cholerae quorum sensing circuit at HCD state 1, but forseen to show any significant response to the CAI-1 variants [44]. In coherence to this, a commensal E. coli manipulated to express the cqsA gene that produced a variant CAI-1 inhibits pathogenesis of V. cholerae in an infant mouse model [45] provides an insight that targeting the stronger signal with its structural and functional mimic would probably lead to the development of an anticholera treatmnt.…”

“…CqsS, a unique TCS system in Vibrio cholerae (CqsSvc) known to be highly conserved (70 %) in the transmembrane ligand sensing domains among all Vibrio species as it detects CAI-1 molecules with the extended side chains either with 10-carbon or 8-carbon [47]. The residues Cys 170 /Phe 175 was found to be crucial in the CqsSvc as it signifies the ligand chain length [44]. The CqsSvc Sensor histidine kinases has a N-terminal transmembrane sensing domains, dimerization histidine phosphotransfer (DHp) domains and C-terminal catalytic ATPbinding (CA) domains [48].…”