The integrity of the cell envelope of E. coli relies on the concerted activity of multi-protein machineries that synthesize the peptidoglycan (PG) and the outer membrane (OM). Our previous work showed that the depletion of lipopolysaccharide (LPS) export to the OM induces an essential PG remodeling process involving LD-transpeptidases (LDTs), the glycosyltransferase function of PBP1B and the carboxypeptidase PBP6a. Consequently, cells with defective OM biogenesis lyse if they lack any of these PG enzymes. Here we report that the morphological defects and lysis associated with a ldtF mutant with impaired LPS transport, are alleviated by the loss of the predicted OM-anchored lipoprotein ActS (formerly YgeR). We show that ActS is an inactive member of LytM-type peptidoglycan endopeptidases due to a degenerate catalytic domain. ActS is capable of activating all three main periplasmic peptidoglycan amidases, AmiA, AmiB and AmiC, which were previously reported to be activated only by EnvC and/or NlpD. Our data also suggest that in vivo ActS preferentially activates AmiC and that its function is linked to cell envelope stress.

ActS activates peptidoglycan amidases during outer membrane stress in Escherichia coli / C.K. Gurnani Serrano, M. Winkle, A.M. Martorana, J. Biboy, N. Mor(`(e)), P. Moynihan, M. Banzhaf, W. Vollmer, A. Polissi. - In: MOLECULAR MICROBIOLOGY. - ISSN 0950-382X. - 116:1(2021 Jul), pp. 329-342. [10.1111/mmi.14712]

ActS activates peptidoglycan amidases during outer membrane stress in Escherichia coli

C.K. Gurnani Serrano
Primo
;
A.M. Martorana;A. Polissi
2021

Abstract

The integrity of the cell envelope of E. coli relies on the concerted activity of multi-protein machineries that synthesize the peptidoglycan (PG) and the outer membrane (OM). Our previous work showed that the depletion of lipopolysaccharide (LPS) export to the OM induces an essential PG remodeling process involving LD-transpeptidases (LDTs), the glycosyltransferase function of PBP1B and the carboxypeptidase PBP6a. Consequently, cells with defective OM biogenesis lyse if they lack any of these PG enzymes. Here we report that the morphological defects and lysis associated with a ldtF mutant with impaired LPS transport, are alleviated by the loss of the predicted OM-anchored lipoprotein ActS (formerly YgeR). We show that ActS is an inactive member of LytM-type peptidoglycan endopeptidases due to a degenerate catalytic domain. ActS is capable of activating all three main periplasmic peptidoglycan amidases, AmiA, AmiB and AmiC, which were previously reported to be activated only by EnvC and/or NlpD. Our data also suggest that in vivo ActS preferentially activates AmiC and that its function is linked to cell envelope stress.
Escherichia coli; cell division; cell envelope; lipopolysaccharide; peptidoglycan
Settore BIO/19 - Microbiologia Generale
An integrated mulTidisciplinary appRoach towards a new generAtIon of aNtibiotics: Targeting function and cross-talk of bacterial Envelope proTein machineries (Train2Target)
4-mar-2021
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/823481
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