Coordination of peptidoglycan synthesis and outer membrane constriction during Escherichia coli cell division

Gray, Andrew N.; Egan, Alexander J F; Veer, Inge L van't; Verheul, Jolanda; Colavin, Alexandre; Koumoutsi, Alexandra; Biboy, Jacob; Altelaar, Maarten; Damen, Mirjam J; Huang, Kerwyn Casey; Simorre, Jean-Pierre; Breukink, Eefjan; Blaauwen, Tanneke den; Typas, Athanasios; Gross, Carol A.; Vollmer, Waldemar

doi:10.7554/elife.07118

Cited by 161 publications

(205 citation statements)

References 98 publications

Supporting

Mentioning

199

Contrasting

Order By: Relevance

“…PBP1b(E313D) suppresses the synthetic lethal interaction between LpoB and Pal without a bridge to the outer membrane. Thus, although recent results further connect the activities of PBP1b and the Tol-Pal system (20), the coordination is unlikely to involve a direct role for the PBP1b-LpoB complex in outer membrane constriction.…”

Section: Discussionmentioning

confidence: 99%

Cofactor bypass variants reveal a conformational control mechanism governing cell wall polymerase activity

Markovski

Bohrhunter

Lupoli

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

To fortify their cytoplasmic membrane and protect it from osmotic rupture, most bacteria surround themselves with a peptidoglycan (PG) exoskeleton synthesized by the penicillin-binding proteins (PBPs). As their name implies, these proteins are the targets of penicillin and related antibiotics. We and others have shown that the PG synthases PBP1b and PBP1a of Escherichia coli require the outer membrane lipoproteins LpoA and LpoB, respectively, for their in vivo function. Although it has been demonstrated that LpoB activates the PG polymerization activity of PBP1b in vitro, the mechanism of activation and its physiological relevance have remained unclear. We therefore selected for variants of PBP1b (PBP1b*) that bypass the LpoB requirement for in vivo function, reasoning that they would shed light on LpoB function and its activation mechanism. Several of these PBP1b variants were isolated and displayed elevated polymerization activity in vitro, indicating that the activation of glycan polymer growth is indeed one of the relevant functions of LpoB in vivo. Moreover, the location of amino acid substitutions causing the bypass phenotype on the PBP1b structure support a model in which polymerization activation proceeds via the induction of a conformational change in PBP1b initiated by LpoB binding to its UB2H domain, followed by its transmission to the glycosyl transferase active site. Finally, phenotypic analysis of strains carrying a PBP1b* variant revealed that the PBP1b-LpoB complex is most likely not providing an important physical link between the inner and outer membranes at the division site, as has been previously proposed.T he peptidoglycan (PG) layer forms a protective shell that surrounds the cytoplasmic membrane of bacteria to prevent osmotic rupture and provide cells with their characteristic shape (1). This complex macromolecule is composed of glycan strands crosslinked to one another by attached peptide chains to form the exoskeletal matrix. Because of its essentiality and uniqueness to bacteria, the PG layer is an important therapeutic target. Many antibiotics in our current arsenal block PG assembly, with penicillin and related beta-lactam drugs being the most wellknown and widely used. These molecules target major PG synthase enzymes called penicillin-binding proteins (PBPs) (1).The PBPs function in the final stage of the three-part pathway for PG biogenesis (1). Precursor synthesis begins in the cytoplasm with the production of the activated sugar molecules uridine diphosphate (UDP)-N-acetylmuramic acid pentapeptide (UDP-MurNAc-pep 5 ) and UDP-N-acetylglucosamine (UDPGlcNAc). In the second, membrane-associated phase, UDPMurNAc-pep 5 is converted to the precursor lipid-I by MraY, which transfers phospho-MurNAc-pep to the lipid carrier undecaprenol-phosphate (Und-P). Lipid-II is formed by MurG via the addition of GlcNAc to lipid-I from UDP-GlcNAc. This final precursor contains the basic monomeric unit of PG, the disaccharide-pentapeptide. After its production, lipid-II must be flipped by MurJ (2, 3) ...

show abstract

Section: Discussionmentioning

confidence: 99%

Cofactor bypass variants reveal a conformational control mechanism governing cell wall polymerase activity

Markovski

Bohrhunter

Lupoli

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…There is a growing body of evidence linking cell division to peptidoglycan synthesis (45)(46)(47)(48)(49)(50). If this is correct, the resulting decrease in peptidoglycan synthesis would then sensitize cells to agents that further disrupt peptidoglycan synthesis, such as ␤-lactams.…”

Section: Figmentioning

confidence: 99%

Mutations Decreasing Intrinsic β-Lactam Resistance Are Linked to Cell Division in the Nosocomial Pathogen Acinetobacter baumannii

Knight

Dimitrova

Rudin

et al. 2016

Antimicrob Agents Chemother

View full text Add to dashboard Cite

eTransposon mutagenesis was used to identify novel determinants of intrinsic ␤-lactam resistance in Acinetobacter baumannii. An EZ-Tn5 transposon insertion in a gene corresponding to the A1S_0225 sequence resulted in a 4-fold decrease in resistance to ampicillin, cefotaxime, imipenem, and ceftriaxone but did not alter resistance to other classes of antibiotics. Based on this phenotype, the gene was designated blhA (␤-lactam hypersusceptibility). The blhA::EZ-Tn5 mutation conferred a similar phenotype in A. baumannii strain ATCC 17978. The wild-type blhA gene complemented the blhA::EZTn5 insertion and restored ␤-lactam resistance levels back to wild-type levels. The blhA mutation also increased ␤-lactam susceptibility in an adeB adeJ double mutant, indicating that the blhA mutation acted independently of these efflux systems to mediate susceptibility. In addition, mRNA levels for the bla OXA and bla ADC ␤-lactamase genes were not altered by the blhA mutation. The blhA mutation resulted in a prominent cell division and morphological defect, with cells exhibiting a highly elongated phenotype, combined with large bulges in some cells. The blhA gene is unique to Acinetobacter and likely represents a novel gene involved in cell division. Three additional mutations, in zipA, zapA, and ftsK, each of which encode predicted cell division proteins, also conferred increased ␤-lactam susceptibility, indicating a common link between cell division and intrinsic ␤-lactam resistance in A. baumannii. The Gram-negative bacterium Acinetobacter baumannii is rapidly becoming an important human pathogen and is associated with infections of the lungs, skin and soft tissues, bloodstream, and urinary tract (1-5). Infections due to this bacterium are primarily health care associated, but the incidence of community-acquired infections is on the rise and may reflect the increased virulence of some strains (6-8). The importance of this bacterium has been recognized by the Infectious Diseases Society of America, who classified it as a member of the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens due to the extensive antibiotic resistances that are present (9, 10). Treatment of this bacterium with antibiotics is becoming increasingly problematic, with decreasing therapeutic options, and in some cases isolates are resistant to all commonly used antibiotics.Intrinsic resistance to the ␤-lactam class of antibiotics in A. baumannii is mediated by a number of mechanisms, including (i) chromosomally encoded ␤-lactamases; (ii) alterations in penicillin binding proteins (PBPs); (iii) efflux via members of the resistance-nodulation-division (RND) family, such as AdeABC and AdeIJK; and (iv) changes in outer membrane permeability (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). The chromosomally encoded ␤-lactamases include those encoded by the bla ADC and bla OXA genes (17-22). Resistance conferred by the bla ADC and bla OXA genes typically ...

show abstract

“…Coordinating synthesis and processing of septal PG is important in Gram-negative bacteria because splitting of septal PG is required for the outer membrane to invaginate. For reasons that are not known, failure of the outer membrane to constrict compromises this important permeability barrier and renders cells susceptible to antibiotics and noxious compounds such as bile salts (16,(55)(56)(57). Several, partially redundant mechanisms help to ensure that the outer membrane constricts in unison with the PG layer and inner membrane (56,(58)(59)(60).…”

Section: Why Target a Division Protein To A Pg Structure Rather Than mentioning

confidence: 99%

“…For reasons that are not known, failure of the outer membrane to constrict compromises this important permeability barrier and renders cells susceptible to antibiotics and noxious compounds such as bile salts (16,(55)(56)(57). Several, partially redundant mechanisms help to ensure that the outer membrane constricts in unison with the PG layer and inner membrane (56,(58)(59)(60). SPOR domains might also contribute to this process by acting as tethers and/or as regulatory factors whose position is fine-tuned by the interplay of the many proteins involved in assembly of the division septum.…”

Section: Why Target a Division Protein To A Pg Structure Rather Than mentioning

confidence: 99%

The SPOR Domain, a Widely Conserved Peptidoglycan Binding Domain That Targets Proteins to the Site of Cell Division

2017

View full text Add to dashboard Cite

Sporulation-related repeat (SPOR) domains are small peptidoglycan (PG) binding domains found in thousands of bacterial proteins. The name "SPOR domain" stems from the fact that several early examples came from proteins involved in sporulation, but SPOR domain proteins are quite diverse and contribute to a variety of processes that involve remodeling of the PG sacculus, especially with respect to cell division. SPOR domains target proteins to the division site by binding to regions of PG devoid of stem peptides ("denuded" glycans), which in turn are enriched in septal PG by the intense, localized activity of cell wall amidases involved in daughter cell separation. This targeting mechanism sets SPOR domain proteins apart from most other septal ring proteins, which localize via protein-protein interactions. In addition to SPOR domains, bacteria contain several other PG-binding domains that can exploit features of the cell wall to target proteins to specific subcellular sites.

show abstract

Coordination of peptidoglycan synthesis and outer membrane constriction during Escherichia coli cell division

Cited by 161 publications

References 98 publications

Cofactor bypass variants reveal a conformational control mechanism governing cell wall polymerase activity

Cofactor bypass variants reveal a conformational control mechanism governing cell wall polymerase activity

Mutations Decreasing Intrinsic β-Lactam Resistance Are Linked to Cell Division in the Nosocomial Pathogen Acinetobacter baumannii

The SPOR Domain, a Widely Conserved Peptidoglycan Binding Domain That Targets Proteins to the Site of Cell Division

Contact Info

Product

Resources

About