Table 2.

Extracellular or intracellular signals that cause envelope stress and induce Rcs system.

Signal	Description	Species	Function	Reference
Lysozyme	N-acetylmuramide glycanohydrolase	E. coli	Destruction of the periplasmic peptidoglycan	Callewaert et al., 2009
β-lactam antibiotics	Chemicals repressing penicillin binding protein (PBPs)	E. coli	Inhibition of peptidoglycan formation and transition to L-form state	Hirakawa et al., 2003; Glover et al., 2009
lolA mutation Ile93-Cys/Phe140Cys	Lipoprotein-specific chaperone lolA	E. coli	Defect in lipoprotein sorting	Tao et al., 2012
pbp4, pbp5, pbp7, or ampH deletion	Penicillin-binding protein pbp4, etc.	E. coli	Modification of the peptidoglycan	Evans et al., 2013
tolA deletion	Periplasm spanning protein tolA	E. coli	Outer membrane perturbation	Morgan et al., 2014
mdoH deletion	mdoH, glucosyltransferase for the synthesis of periplasmic membrane-derived oligosaccharides	E. coli	Defect in membrane-derived oligosaccharides synthesis	Shiba et al., 2012
The concentration of OPGs	OPGs, osmoregulated periplasmic glucans	D. dadantii	Sensing the osmolarity of medium	Bontemps-Gallo et al., 2013
ugd deletion	UDP-glucose dehydrogenase ugd	E. tarda	Defect in LPS, a truncated core with no O-antigen attached	Lv et al., 2012
wecG mutation	ManNAcA transferases wecG	S. marcescens	Alteration in the enterobacterial common antigen (ECA) structure	Castelli and Vescovi, 2011