Communication across the bacterial cell envelope depends on the size of the periplasm

• DOI: 10.1371/journal.pbio.2004303
• Publication Date: 2017-12-19T18:24:47Z
• Authors: Abir T. Asmar; Josie L. Ferreira; Eli J. Cohen; Seung-Hyun Cho; Morgan Beeby; Kelly T. Hughes; Jean-François Collet
• Keywords: Cell envelope; Inner membrane; Cellular compartment; Envelope (radar)

The cell envelope of gram-negative bacteria, a structure comprising an outer (OM) and inner (IM) membrane, is essential for life. OM the IM are separated by periplasm, compartment that contains peptidoglycan. tethered to peptidoglycan via lipoprotein, Lpp. However, importance envelope's multilayered architecture remains unknown. Here, when we removed physical coupling between peptidoglycan, cells lost ability sense defects in integrity. Further experiments revealed critical parameter transmission stress signals from cytoplasm, where cellular behaviour controlled, IM-to-OM distance. Augmenting this distance increasing length lipoprotein Lpp destroyed signalling, whereas simultaneously stress-sensing RcsF restored signalling. Our results demonstrate physiological size periplasm. They also reveal strict control over required effective surveillance protection, suggesting transenvelope protein complexes have been evolutionarily co-optimised correct function. Similar strategies likely at play compartments surrounded 2 concentric membranes, such as chloroplasts mitochondria.