Outer membrane-anchoring enables LpoB to regulate peptidoglycan synthesis rate

Kermani, Ali A.; Biboy, Jacob; Vollmer, Daniela; Vollmer, Waldemar

doi:10.1016/j.tcsw.2022.100086

Cited by 4 publications

(2 citation statements)

References 41 publications

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“…This observation is consistent with the recent findings that outer membrane-anchored LpoB regulates PBP1B in response to osmotic challenges (upon upshift in salt or sucrose concentration). This regulation is partly lost in cells with cytoplasmic membrane-mislocalized LpoB, which have reduced sickness in high salt ( 4 , 53 ), demonstrating that the LpoB-mediated regulation of PBP1B is responsive to media osmolarity and salt concentration. This led us to investigate the effects of salt on the activities of purified PBP1A and PBP1B.…”

Section: Discussionmentioning

confidence: 99%

Reduced peptidoglycan synthesis capacity impairs growth of E. coli at high salt concentration

Alodaini,

Hernandez-Rocamora,

Boelter

et al. 2024

mBio

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Gram-negative bacteria have a thin peptidoglycan layer between the cytoplasmic and outer membranes protecting the cell from osmotic challenges. Hydrolases of this structure are needed to cleave bonds to allow the newly synthesized peptidoglycan strands to be inserted by synthases. These enzymes need to be tightly regulated and their activities coordinated to prevent cell lysis. To better understand this process in Escherichia coli , we probed the genetic interactions of mrcA (encodes PBP1A) and mrcB (encodes PBP1B) with genes encoding peptidoglycan amidases and endopeptidases in envelope stress conditions. Our extensive genetic interaction network analysis revealed relatively few combinations of hydrolase gene deletions with reduced fitness in the absence of PBP1A or PBP1B, showing that none of the amidases or endopeptidases is strictly required for the functioning of one of the class A PBPs. This illustrates the robustness of the peptidoglycan growth mechanism. However, we discovered that the fitness of ∆ mrcB cells is significantly reduced under high salt stress and in vitro activity assays suggest that this phenotype is caused by a reduced peptidoglycan synthesis activity of PBP1A at high salt concentration. IMPORTANCE Escherichia coli and many other bacteria have a surprisingly high number of peptidoglycan hydrolases. These enzymes function in concert with synthases to facilitate the expansion of the peptidoglycan sacculus under a range of growth and stress conditions. The synthases PBP1A and PBP1B both contribute to peptidoglycan expansion during cell division and growth. Our genetic interaction analysis revealed that these two penicillin-binding proteins (PBPs) do not need specific amidases, endopeptidases, or lytic transglycosylases for function. We show that PBP1A and PBP1B do not work equally well when cells encounter high salt stress and demonstrate that PBP1A alone cannot provide sufficient PG synthesis activity under this condition. These results show how the two class A PBPs and peptidoglycan hydrolases govern cell envelope integrity in E. coli in response to environmental challenges and particularly highlight the importance of PBP1B in maintaining cell fitness under high salt conditions.

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Section: Discussionmentioning

confidence: 99%

Reduced peptidoglycan synthesis capacity impairs growth of E. coli at high salt concentration

Alodaini,

Hernandez-Rocamora,

Boelter

et al. 2024

mBio

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“…In fact, LpoA not only modulates PG crosslinking but is also required for PBP1a to form PG glycan strands. Concerning LpoB, it regulates the PG synthesis rate by spanning the periplasm and reaching its cognate PG synthase, PBP1b [77]. In B. subtilis, no essential regulator of PBPs has been highlighted thus far, but the non-essential TseB protein was proposed to regulate PBP2a, a bPBP [78].…”

Section: Regulation Of Pbpsmentioning

confidence: 99%

Recent Advances in Peptidoglycan Synthesis and Regulation in Bacteria

et al. 2023

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Bacteria must synthesize their cell wall and membrane during their cell cycle, with peptidoglycan being the primary component of the cell wall in most bacteria. Peptidoglycan is a three-dimensional polymer that enables bacteria to resist cytoplasmic osmotic pressure, maintain their cell shape and protect themselves from environmental threats. Numerous antibiotics that are currently used target enzymes involved in the synthesis of the cell wall, particularly peptidoglycan synthases. In this review, we highlight recent progress in our understanding of peptidoglycan synthesis, remodeling, repair, and regulation in two model bacteria: the Gram-negative Escherichia coli and the Gram-positive Bacillus subtilis. By summarizing the latest findings in this field, we hope to provide a comprehensive overview of peptidoglycan biology, which is critical for our understanding of bacterial adaptation and antibiotic resistance.

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Intranasal immunization with poly I:C and CpG ODN adjuvants enhances the protective efficacy against Helicobacter pylori infection in mice

Sun,

Liu,

et al. 2024

Microbes and Infection

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Outer membrane-anchoring enables LpoB to regulate peptidoglycan synthesis rate

Cited by 4 publications

References 41 publications

Reduced peptidoglycan synthesis capacity impairs growth of E. coli at high salt concentration

Reduced peptidoglycan synthesis capacity impairs growth of E. coli at high salt concentration

Recent Advances in Peptidoglycan Synthesis and Regulation in Bacteria

Intranasal immunization with poly I:C and CpG ODN adjuvants enhances the protective efficacy against Helicobacter pylori infection in mice

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