Intermembrane crosstalk drives inner-membrane protein organization in Escherichia coli

• DOI: 10.1038/s41467-018-03521-4
• Publication Date: 2018-03-08T17:53:15Z
• Authors: Patrice Rassam; Kathleen R. Long; Renata Kaminska; David J. Williams; Grigorios Papadakos; Christoph G. Baumann; Colin Kleanthous
• Keywords: Colicin; Cell envelope; Inner membrane; Cell membrane; Transport protein

Abstract Gram-negative bacteria depend on energised protein complexes that connect the two membranes of cell envelope. However, β-barrel outer-membrane proteins (OMPs) and α-helical inner-membrane (IMPs) display quite different organisation. OMPs cluster into islands restrict their lateral mobility, while IMPs generally diffuse throughout cell. Here, using live imaging Escherichia coli , we demonstrate when transient, energy-dependent transmembrane connections are formed, become subjugated by inherent organisation such impact IMP function. We show establishing a translocon for import, colicin ColE9 sequesters proton motive force (PMF)-linked Tol-Pal complex mirroring those colicin-bound OMPs. Through this imposed organisation, bacteriocin subverts stabilising role Tol-Pal, blocking its recruitment to division sites slowing membrane constriction. The ordering via an inter-membrane bridge represents emerging functional paradigm in envelope biology.