Detecting Envelope Stress by Monitoring beta-Barrel Assembly

作者：Cho Seung Hyun; Szewczyk Joanna; Pesavento Christina; Zietek Matylda; Banzhaf Manuel; Roszczenko Paula; Asmar Abir; Laloux Geraldine; Hov Ann Kristin; Leverrier Pauline; Van der Henst Charles; Vertommen Didier; Typas Athanasios^*; Collet Jean Francois

来源：Cell, 2014, 159(7): 1652-1664.

DOI：10.1016/j.cell.2014.11.045

The cell envelope protects bacteria from their surroundings. Defects in its integrity or assembly are sensed by signal transduction systems, allowing cells to rapidly adjust. The Rcs phosphorelay responds to outer membrane (OM)- and peptidoglycan-related stress in enterobacteria. We elucidated how the OM lipoprotein RcsF, the upstream Rcs component, senses envelope stress and activates the signaling cascade. RcsF interacts with BamA, the major component of the beta-barrel assembly machinery. In growing cells, BamA continuously funnels RcsF through the beta-barrel OmpA, displaying RcsF on the cell surface. This process spatially separates RcsF from the downstream Rcs component, which we show is the inner membrane protein IgaA. The Rcs system is activated when BamA fails to bind RcsF and funnel it to OmpA. Newly synthesized RcsF then remains periplasmic, interacting with IgaA to activate the cascade. Thus RcsF senses envelope damage by monitoring the activity of the Bam machinery.

• 出版日期2014-12-18