Autoinducer-1 quorum sensing pathway (AI-1 QS)

The Autoinducer-1 (AI-1) quorum sensing pathway is a primary communication system used by Gram-negative bacteria to coordinate collective behaviors based on population density (Miller & Bassler, 2001). It typically consists of a LuxI-type synthase that produces signaling molecules known as N-acyl homoserine lactones (AHLs) and a cognate LuxR-type receptor that acts as a signal-dependent transcription factor (Papenfort & Bassler, 2016). When the concentration of AHLs reaches a critical threshold, they bind to the LuxR receptor, triggering the expression of genes involved in virulence, biofilm formation, and antibiotic resistance (Rutherford & Bassler, 2012). Targeting this pathway, a strategy known as quorum quenching, aims to disarm pathogens without killing them, potentially reducing the selective pressure for antibiotic resistance (Defoirdt, 2018). This approach is particularly relevant for treating chronic infections caused by pathogens like Pseudomonas aeruginosa, where AI-1 signaling regulates the production of destructive enzymes and toxins (Whiteley et al., 2017). Small molecule inhibitors and enzymes that degrade AHLs are currently being explored as therapeutic agents to enhance the efficacy of traditional antibiotics (Dong et al., 2001). However, challenges remain regarding the specificity of these agents and their potential impact on the host's commensal microbiome (Zhang & Li, 2016).

Other names

LuxI/LuxR systemN-acyl homoserine lactone signaling pathwayAHL quorum sensing systemGram-negative quorum sensing pathway

Competitive antagonism of LuxR-type receptors, inhibition of LuxI-type AHL synthases, and enzymatic degradation of AHL signaling molecules (quorum quenching).