Removal of a Membrane Anchor Reveals the Opposing Regulatory Functions of Vibrio cholerae Glucose-Specific Enzyme IIA in Biofilms and the Mammalian Intestine, Vijayakumar et al

The phosphoenolpyruvate phosphotransferase system (PTS) is a phosphotransfer cascade that regulates bacterial metabolism, behavior, and the transport of many sugars.  Glucose-specific enzyme IIA (EllAGlc) is component of the PTS that carries out phosphotransfer and regulates both membrane-associated and cytoplasmic partners through direct protein-protein interactions.  Here Vijayakumar et al identify an amphipathic helix at the N-terminus of Vibrio cholerae EIIAGlc that enables this protein to associate with the inner membrane.  This amphipathic helix is essential for EIIAGlc regulation of membrane-associated partners, and Dr. Vijayakumar shows that unrelated amphipathic helices can rescue function.  Removal of this amphipathic helix uncouples phosphotransfer through the PTS from sugar transport.  Finally, Dr. Vijayakumar shows that EIIAGlc regulates opposing cytoplasmic  and membrane-associated regulators of biofilm formation and bacterial metabolism in the mammalian intestine whose activities may be studied in isolation by removal of the amphipathic helix.

https://mbio.asm.org/content/9/5/e00858-18.long

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The EIIAGlc amphipathic helix

A self-assembling whole cell vaccine antigen presentation platform, Liao et al

Here Liao and colleagues describe an antigen presentation platform based on fusion of antigens to the Vibrio cholerae biofilm matrix protein RbmA with delivery in the form of a whole cell, live-attenuated vaccine.  We show that fusion of the B subunit of cholera toxin (CTB) to RbmA and presentation via sublingual delivery of whole cells results in a mucosal immune response to both the V. cholerae O-antigen and CTB.

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From the cover!

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Activation of Vibrio cholerae quorum sensing promotes survival of an arthropod host, Kamareddine and Wong et al

The Vibrio cholerae quorum sensing master regulator HapR represses virulence factor expression and biofilm formation at high cell density.  In this manuscript, we show that V. cholerae quorum sensing decreases pathogen virulence in the model arthropod, Drosophila melanogaster.  We show that this decrease in virulence can be attributed to repression of succinate uptake by HapR.  Infection with a HapR mutant results in depletion of host lipid stores and host death.  Dietary supplementation with succinate allows the host to retain its lipid stores, thus prolonging survival.

Mammalian and arthropod hosts depend on the metabolic signals generated by intestinal bacteria to maintain homeostasis.  While pathogens can disrupt homeostasis by consuming these metabolic signals, our study reveals a novel role for V. cholerae quorum sensing in repressing bacterial consumption of succinate to ensure nutritional cooperation of this pathogen with its arthropod host.

manuscript link

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Consumption of dietary methionine sulfoxide by intestinal pathogens as a virulence strategy, Vanhove et al

Vibrio cholerae ensures function of host proteins required for virulence through consumption of luminal methionine sulfoxide

PLoS Pathogens, 2017;13(6):e1006428

Vanhove AS, Hang S, Vijayakumar V, Wong CN, Asara JM, Watnick PI.

Using the fly as a model, Audrey Vanhove and Saiyu Hang have discovered a novel virulence mechanism of intestinal pathogens in which consumption of dietary methionine sulfoxide by V. cholerae liberates host methionine sulfoxide reductase to repair oxidized host intestinal proteins required for virulence.

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