Intermembrane Crosstalk in E. coli

We have previously described how promiscuous protein-protein interactions between outer membrane proteins (OMPs) cause them to self-associate into large platforms, which we call OMP islands, and that these supramolecular assemblies are the basis by which OMPs are turned over in bacterial populations (Rassam et al., Nature, 2015; Kleanthous et al., Current Opinion in Structural Biology, 2015). Combining advanced microscopy methods with new analytical tools, we have discovered that the organisation inherent in the bacterial outer membrane is reflected in the inner membrane when the two become connected by a protein bridge. Periplasmic protein bridges serve many important functions in Gram-negative bacteria, including secreting lipopolysaccharides and virulence factors to the cell surface and importing iron siderophores across the outer membrane. Current work is aimed at determing the biological consequences of this outer-inner membrane cross-talk.