Schwechheimer, C. & Kuehn, M. J. Outer-membrane vesicles from Gram-negative bacteria: biogenesis and functions. Nat. Rev. Microbiol. 13, 605–619 (2015).


Google Scholar
 

Park, J. et al. A novel decoy strategy for polymyxin resistance in Acinetobacter baumannii. eLife 10, e66988 (2021).


Google Scholar
 

Sartorio, M. G., Pardue, E. J., Feldman, M. F. & Haurat, M. F. Bacterial outer membrane vesicles: from discovery to applications. Annu. Rev. Microbiol. 75, 609–630 (2021).


Google Scholar
 

Li, C. et al. T6SS secretes an LPS-binding effector to recruit OMVs for exploitative competition and horizontal gene transfer. ISME J. 16, 500–510 (2022).


Google Scholar
 

Juodeikis, R. & Carding, S. R. Outer membrane vesicles: biogenesis, functions, and issues. Microbiol. Mol. Biol. Rev. 86, e0003222 (2022).


Google Scholar
 

McMillan, H. M. & Kuehn, M. J. The extracellular vesicle generation paradox: a bacterial point of view. EMBO J. 40, e108174 (2021).


Google Scholar
 

Caruana, J. C. & Walper, S. A. Bacterial membrane vesicles as mediators of microbe-microbe and microbe-host community interactions. Front. Microbiol. 11, 432 (2020).


Google Scholar
 

Clairfeuille, T. et al. Structure of the essential inner membrane lipopolysaccharide–PbgA complex. Nature 584, 479–483 (2020).


Google Scholar
 

Shen, Z. et al. Outer membrane vesicles mediating horizontal transfer of the epidemic bla(OXA-232) carbapenemase gene among Enterobacterales. Emerg. Microbes Infect. 13, 2290840 (2024).


Google Scholar
 

Zhao, X., Wei, Y., Bu, Y., Ren, X. & Dong, Z. Review on bacterial outer membrane vesicles: structure, vesicle formation, separation and biotechnological applications. Microb. Cell Fact. 24, 27 (2025).


Google Scholar
 

Flannagan, R. S., Aubert, D., Kooi, C., Sokol, P. A. & Valvano, M. A. Burkholderia cenocepacia requires a periplasmic HtrA protease for growth under thermal and osmotic stress and for survival in vivo. Infect. Immun. 75, 1679–1689 (2007).


Google Scholar
 

Fu, X. et al. DegP functions as a critical protease for bacterial acid resistance. FEBS J. 285, 3525–3538 (2018).


Google Scholar
 

Leandro, M. R. et al. DegP protease is essential for tolerance to salt stress in the plant growth-promoting bacterium Gluconacetobacter diazotrophicus PAL5. Microbiol. Res. 243, 126654 (2021).


Google Scholar
 

Šulskis, D., Thoma, J. & Burmann, B. M. Structural basis of DegP protease temperature-dependent activation. Sci. Adv. 7, eabj1816 (2021).


Google Scholar
 

McBroom, A. J., Johnson, A. P., Vemulapalli, S. & Kuehn, M. J. Outer membrane vesicle production by Escherichia coli is independent of membrane instability. J. Bacteriol. 188, 5385–5392 (2006).


Google Scholar
 

Birkle, K. et al. An unprecedented tolerance to deletion of the periplasmic chaperones SurA, Skp, and DegP in the nosocomial pathogen Acinetobacter baumannii. J. Bacteriol. 204, e00054-22 (2022).


Google Scholar
 

Kim, S. Y. et al. The sensor kinase BfmS controls production of outer membrane vesicles in Acinetobacter baumannii. BMC Microbiol. 19, 301 (2019).


Google Scholar
 

Schwechheimer, C. & Kuehn, M. J. Synthetic effect between envelope stress and lack of outer membrane vesicle production in Escherichia coli. J. Bacteriol. 195, 4161–4173 (2013).


Google Scholar
 

Sonntag, I., Schwarz, H., Hirota, Y. & Henning, U. Cell envelope and shape of Escherichia coli: multiple mutants missing the outer membrane lipoprotein and other major outer membrane proteins. J. Bacteriol. 136, 280–285 (1978).


Google Scholar
 

Takaki, K. et al. Multilamellar and multivesicular outer membrane vesicles produced by a Buttiauxella agrestis tolB mutant. App. Environ. Microbiol. 86, e01131–20 (2020).


Google Scholar
 

McBroom, A. J. & Kuehn, M. J. Release of outer membrane vesicles by Gram-negative bacteria is a novel envelope stress response. Mol. Microbiol. 63, 545–558 (2007).


Google Scholar
 

Bernadac, A., Gavioli, M., Lazzaroni, J. C., Raina, S. & Lloubès, R. Escherichia coli tol-pal mutants form outer membrane vesicles. J. Bacteriol. 180, 4872–4878 (1998).


Google Scholar
 

Betton, J. M., Boscus, D., Missiakas, D., Raina, S. & Hofnung, M. Probing the structural role of an alpha beta loop of maltose-binding protein by mutagenesis: heat-shock induction by loop variants of the maltose-binding protein that form periplasmic inclusion bodies. J. Mol. Biol. 262, 140–150 (1996).


Google Scholar
 

Mathelié-Guinlet, M., Asmar, A. T., Collet, J. F. & Dufrêne, Y. F. Lipoprotein Lpp regulates the mechanical properties of the E. coli cell envelope. Nat. Commun. 11, 1789 (2020).


Google Scholar
 

Rojas, E. R. et al. The outer membrane is an essential load-bearing element in Gram-negative bacteria. Nature 559, 617–621 (2018).


Google Scholar
 

Fenn, K. L. et al. Outer membrane protein assembly mediated by BAM-SurA complexes. Nat. Commun. 15, 7612 (2024).


Google Scholar
 

Bryant, J. A. et al. Bam complex associated proteins in Escherichia coli are functionally linked to peptidoglycan biosynthesis, membrane fluidity and DNA replication. eLife 13, RP99955 (2024).

Chamachi, N. et al. Chaperones Skp and SurA dynamically expand unfolded OmpX and synergistically disassemble oligomeric aggregates. PNAS 119, e2118919119 (2022).


Google Scholar
 

Subrini, O. & Betton, J. M. Assemblies of DegP underlie its dual chaperone and protease function. FEMS Microbiol. Lett. 296, 143–148 (2009).


Google Scholar
 

Gilmore, M. C. & Cava, F. Peptidoglycan recycling mediated by an ABC transporter in the plant pathogen Agrobacterium tumefaciens. Nat. Commun. 13, 7927 (2022).


Google Scholar
 

Simpson, B. W., Gilmore, M. C., McLean, A. B., Cava, F. & Trent, M. S. Escherichia coli utilizes multiple peptidoglycan recycling permeases with distinct strategies of recycling. PNAS 120, e2308940120 (2023).


Google Scholar
 

Sverak, H. E. et al. Cryo-EM characterization of the anydromuropeptide permease AmpG central to bacterial fitness and β-lactam antibiotic resistance. Nat. Commun. 15, 9936 (2024).


Google Scholar
 

Hayashi, J.-I., Hamada, N. & Kuramitsu, H. K. The autolysin of Porphyromonas gingivalis is involved in outer membrane vesicle release. FEMS Microbiol. Lett. 216, 217–222 (2002).


Google Scholar
 

Schwechheimer, C., Rodriguez, D. L. & Kuehn, M. J. NlpI-mediated modulation of outer membrane vesicle production through peptidoglycan dynamics in Escherichia coli. Microbiologyopen 4, 375–389 (2015).


Google Scholar
 

Egan, A. J. F., Errington, J. & Vollmer, W. Regulation of peptidoglycan synthesis and remodelling. Nat. Rev. Microbiol. 18, 446–460 (2020).


Google Scholar
 

Garde, S., Chodisetti, P. K. & Reddy, M. Peptidoglycan: structure, synthesis, and regulation. EcoSal Plus. 9, (2021).

Dik, D. A., Marous, D. R., Fisher, J. F. & Mobashery, S. Lytic transglycosylases: concinnity in concision of the bacterial cell wall. Crit. Rev. Biochem. Mol. Biol. 52, 503–542 (2017).


Google Scholar
 

Kaul, M., Meher, S. K., Nallamotu, K. C. & Reddy, M. Glycan strand cleavage by a lytic transglycosylase, MltD contributes to the expansion of peptidoglycan in Escherichia coli. PLoS Genet. 20, e1011161 (2024).


Google Scholar
 

Hoang, Y. et al. An experimental framework to assess biomolecular condensates in bacteria. Nat. Commun. 15, 3222 (2024).


Google Scholar
 

Ma, B., Reynolds, C. M. & Raetz, C. R. H. Periplasmic orientation of nascent lipid A in the inner membrane of an Escherichia coli LptA mutant. Proc. Natl. Acad. Sci. USA. 105, 13823–13828 (2008).


Google Scholar
 

Morán-Barrio, J. et al. The lipoprotein biosynthesis pathway: key to OXA-mediated carbapenem resistance in Acinetobacter baumannii. Antimicrob. Agents Chemother. 69, e0109925 (2025).


Google Scholar
 

Huang, K. et al. Deletion of a previously uncharacterized lipoprotein lirL confers resistance to an inhibitor of type II signal peptidase in Acinetobacter baumannii. Proc. Natl. Acad. Sci. USA. 119, e2123117119 (2022).


Google Scholar
 

Martorana, A. M. et al. Degradation of components of the Lpt transenvelope machinery reveals LPS-dependent Lpt complex stability in Escherichia coli. Front. Mol. Biosci. 8, 758228 (2021).


Google Scholar
 

Son, Y. et al. Unexpected vulnerability of Enterococcus faecium to polymyxin B under anaerobic condition. Gut Microbes 16, 2438465 (2024).


Google Scholar
 

Yang, J., Yun, S. & Park, W. Blue Light Sensing BlsA-mediated modulation of meropenem resistance and biofilm formation in Acinetobacter baumannii. mSystems 8, e00897-22 (2023).


Google Scholar
 

Manioglu, S. et al. Antibiotic polymyxin arranges lipopolysaccharide into crystalline structures to solidify the bacterial membrane. Nat. Commun. 13, 6195 (2022).


Google Scholar
 

Marotta, J., May, K. L., Bae, C. Y. & Grabowicz, M. Molecular insights into Escherichia coli Cpx envelope stress response activation by the sensor lipoprotein NlpE. Mol. Microbiol. 119, 586–598 (2023).


Google Scholar
 

Roch, M. et al. Thermosensitive PBP2a requires extracellular folding factors PrsA and HtrA1 for Staphylococcus aureus MRSA β-lactam resistance. Commun. Biol. 2, 417 (2019).


Google Scholar
 

Penwell, W. F. et al. Molecular mechanisms of sulbactam antibacterial activity and resistance determinants in Acinetobacter baumannii. AAC 59, 1680–1689 (2015).


Google Scholar
 

Kocaoglu, O. & Carlson, E. E. Profiling of β-lactam selectivity for penicillin-binding proteins in Escherichia coli Strain DC2. AAC 59, 2785–2790 (2015).


Google Scholar
 

Crépin, S. et al. The lytic transglycosylase MltB connects membrane homeostasis and in vivo fitness of Acinetobacter baumannii. Mol. Microbiol. 109, 745–762 (2018).

Le, N. H. et al. Peptidoglycan editing provides immunity to Acinetobacter baumannii during bacterial warfare. Sci. Adv. 6, eabb5614 (2020).


Google Scholar
 

Raustad, N. et al. A phosphorylation signal activates genome-wide transcriptional control by BfmR, the global regulator of Acinetobacter resistance and virulence. Nucleic Acids Res. 53, gkaf063 (2025).

Rao, S. et al. Characterizing membrane association and periplasmic transfer of bacterial lipoproteins through molecular dynamics simulations. Structure 28, 475–487.e3 (2020).


Google Scholar
 

Micelli, C. et al. A conserved zinc-binding site in Acinetobacter baumannii PBP2 required for elongasome-directed bacterial cell shape. PNAS 120, e2215237120 (2023).


Google Scholar
 

May, K. L., Lehman, K. M., Mitchell, A. M. & Grabowicz, M. A stress response monitoring lipoprotein trafficking to the outer membrane. mBio 10, e00618-19 (2019).

Gottesman, S. Proteases and their targets in Escherichia coli. Annu. Rev. Genet. 30, 465–506 (1996).


Google Scholar
 

Soltes, G. R., Martin, N. R., Park, E., Sutterlin, H. A. & Silhavy, T. J. Distinctive roles for periplasmic proteases in the maintenance of essential outer membrane protein assembly. J. Bacteriol. 199, 10 (2017).


Google Scholar
 

Birkle, K. et al. An unprecedented tolerance to deletion of the periplasmic chaperones SurA, Skp, and DegP in the nosocomial pathogen Acinetobacter baumannii. J. Bacteriol. 204, e00054–2 (2022).


Google Scholar
 

Spiess, C., Beil, A. & Ehrmann, M. A temperature-dependent switch from chaperone to protease in a widely conserved heat shock protein. Cell 97, 339–347 (1999).


Google Scholar
 

Krojer, T., Garrido-Franco, M., Huber, R., Ehrmann, M. & Clausen, T. Crystal structure of DegP (HtrA) reveals a new protease-chaperone machine. Nature 416, 455–459 (2022).


Google Scholar
 

Fantappiè, L., Irene, C., De Santis, M., Armini, A. & Gagliardi, A. Some Gram-negative lipoproteins keep their surface topology when transplanted from one species to another and deliver foreign polypeptides to the bacterial surface. Mol Cell Proteomics 16, 1348–1364 (2017).


Google Scholar
 

Raivio, T. L., Leblanc, S. K. & Price, N. L. The Escherichia coli Cpx envelope stress response regulates genes of diverse function that impact antibiotic resistance and membrane integrity. J. Bacteriol. 195, 2755–2767 (2014).


Google Scholar
 

Cian, M. B., Giordano, N. P., Mettlach, J. A., Minor, K. E. & Dalebroux, Z. D. Separation of the cell envelope for Gram-negative bacteria into inner and outer membrane fractions with technical adjustments for Acinetobacter baumannii. J. Vis. Exp. 10, 10.3791-60517 (2020).

Cho, T. H. S., Wang, J. & Raivio, T. L. NlpE is an OmpA-associated outer membrane sensor of the Cpx envelope stress response. J. Bacteriol. 205, e00407-22 (2023).


Google Scholar
 

Lin, M. F., Lin, Y. Y. & Lan, C. Y. The role of the two-component system BaeSR in disposing chemicals through regulating transporter systems in Acinetobacter baumannii. PLoS ONE 10, e0132843 (2015).


Google Scholar
 

Palethorpe, S. et al. Acinetobacter baumannii Regulates its stress responses via the BfmRS two-component regulatory system. J. Bacteriol. 204, e0049421 (2022).


Google Scholar
 

Laloux, G. & Collet, J. F. Major Tom to ground control: how lipoproteins communicate extracytoplasmic stress to the decision center of the cell. J. Bacteriol. 199, 3 (2017).


Google Scholar
 

Delhaye, A., Collet, J. F. & Laloux, G. Fine-tuning of the Cpx envelope stress response is required for cell wall homeostasis in Escherichia coli. mBio 7, 1128 (2016).


Google Scholar
 

Price, N. L. & Raivio, T. L. Characterization of the Cpx regulon in Escherichia coli strain MC4100. J. Bacteriol. 191, 1798–1815 (2009).


Google Scholar
 

Raivio, T. L., Leblanc, S. K. & Price, N. L. The Escherichia coli Cpx envelope stress response regulates genes of diverse function that impact antibiotic resistance and membrane integrity. J. Bacteriol. 195, 2755–2767 (2013).


Google Scholar
 

Scheurwater, E., Reid, C. W. & Clarke, A. J. Lytic transglycosylases: bacterial space-making autolysins. Int. J. Biochem. Cell Biol. 40, 586–591 (2007).


Google Scholar
 

Avila-Cobian, L. F., De Benedetti, S., Kim, C., Feltzer, R. & Champion, M. M. In vitro studies of the protein-interaction network of cell-wall lytic transglycosylase RlpA of Pseudomonas aeruginosa. Commun. Biol. 5, 1314 (2022).


Google Scholar
 

Lee, M. et al. Reactions of all Escherichia coli lytic transglycosylases with bacterial cell wall. J. Am. Chem. Soc. 135, 3311–3314 (2013).


Google Scholar
 

Weaver, A. I. et al. Lytic transglycosylases RlpA and MltC assist in Vibrio cholerae daughter cell separation. Mol. Microbiol. 112, 1100–1115 (2019).


Google Scholar
 

Alvarez, L. et al. Control of bacterial cell wall autolysins by peptidoglycan crosslinking mode. Nat. Commun. 15, 7937 (2024).


Google Scholar
 

Yunck, R., Cho, H. & Bernhardt, T. G. Identification of MltG as a potential terminase for peptidoglycan polymerization in bacteria. Mol. Microbiol. 99, 700–718 (2016).

Sassine, J., Pazos, M., Breukink, E. & Vollmer, W. Lytic transglycosylase MltG cleaves in nascent peptidoglycan and produces short glycan strands. Cell Surf. 7, 100053 (2021).


Google Scholar
 

White, C. L. & Gober, J. W. MreB: pilot or passenger of cell wall synthesis? Trends Microbiol. 20, 74–79 (2012).


Google Scholar
 

Yun, S. et al. Experimental evolution under different nutritional conditions changes the genomic architecture and virulence of Acinetobacter baumannii. Commun. Biol. 7, 1274 (2024).

Yang, J., Son, Y., Kang, M. & Park, W. AamA-mediated epigenetic control of genome-wide gene expression and phenotypic traits in Acinetobacter baumannii ATCC 17978. Microbial Genomics 9, 001093 (2023).

Wang, Y. et al. A highly efficient CRISPR-Cas9-based genome engineering platform in Acinetobacter baumannii to understand the H2O2-sensing mechanism of OxyR. Cell Chem. Biol. 26, 1732–1742.e5 (2019).


Google Scholar
 

Park, Y. et al. Alleviation of H2O2 toxicity by extracellular catalases in the phycosphere of Microcystis aeruginosa. Harmful Algae 137, 102680 (2024).

Choi, J. et al. Efficient hepatic differentiation and regeneration potential under xeno-free conditions using mass-producible amnion-derived mesenchymal stem cells. Stem Cell Res. Ther. 12, 569 (2021).


Google Scholar
 

Cian, M. B., Giordano, N. P., Mettlach, J. A., Minor, K. E. & Dalebroux, Z. D. Separation of the cell envelope for Gram-negative bacteria into inner and outer membrane fractions with technical adjustments for Acinetobacter baumannii. J. Vis. Exp. 10, 10 (2020).

Damke, P. P. et al. Identification of the periplasmic DNA receptor for natural transformation of Helicobacter pylori. Nat. Commun. 10, 5357 (2019).


Google Scholar
 

Simpson, B. W. et al. Acinetobacter baumannii can survive with an outer membrane lacking lipooligosaccharide due to structural support from elongasome peptidoglycan synseparatemutantsthesis. mBio 12, e03099-21 (2021).


Google Scholar
 

Vroom, M. M. et al. Modeled microgravity alters lipopolysaccharide and outer membrane vesicle production of the beneficial symbiont Vibrio fischeri. npj Microgravity 7, 8 (2021).


Google Scholar
 

Matano, C. et al. Corynebacterium glutamicum possesses β-N-acetylglucosaminidase. BMC Microbiol. 16, 177 (2016).


Google Scholar