Figure 1. Schematic overview of AI‐2‐mediated quorum sensing in Escherichia coli .
Autoinducer‐2 is a quorum sensing signal molecule that mediates interspecies and inter‐kingdom cell‐to‐cell communication. The four predicted AI‐2 exporters from E. coli are shown embedded in the inner membrane in different shades (TqsA in yellow, YdiK in blue, YhhT in red, and PerM in brown), and AI‐2 is represented as small red pentagonal moieties. LuxS produces DPD, the precursor of AI‐2. The ABC transporter complex LsrABCD is involved in the active import of AI‐2. Phosphorylated AI‐2 inactivates the transcriptional repressor and thereby regulates the expression of quorum sensing‐related genes.