Author: pwatnick

Bat, who collaborated with Layla Kamareddine early on, shows that acetate produced by the microbiota enters the cell through an acetate transporter he named Tarag. From there it is converted to acetyl-CoA and used by the histone acetyltransferase Tip60 complex to acetylate histone 2Av, which activates transcription of ecdysone-induced genes including the peptidoglycan receptor PGRP-LC. He proposes that the increase in PGRP-LC transcription potentiates innate immune signaling in the intestine. This leads to increased antimicrobial peptide expression and increased expression of tachykinin, an inhibitor of lipid synthesis in the gut. This provides a template for how microbiota might influence the innate immune response of the intestinal epithelium.

Here is a link to his paper:

https://authors.elsevier.com/a/1dCgc3qNrUmRJx

Congratulations Layla!!! Former Watnick lab postdoc and current Assistant Professor at Qatar University, Dr. Layla Kamareddine wins first prize in for her poster: Between Immunity, Metabolism, and Development: A story of a Fly Gut! at the Annual Research Forum & Exhibition November, 2020; Doha, Qatar.

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Fernanda reviews the complex interaction between sex steroids, the innate immune response, and the microbiota in the mammalian intestine! DOI: 10.1016/j.tim.2020.11.001

Methionine availability in the arthropod intestine is elucidated through identification of Vibrio cholerae methionine acquisition systems.

An approach to understanding conditions in the host intestine by defining pathogen nutrient uptake systems.

Audrey S. Vanhove, Bat-Erdene Jugder, Daniela Barraza, and Paula I. Watnick

DOI: 10.1128/AEM.00371-20

Hypothesis: Microbes activate mechanical, metabolic, and antibacterial branches of the IMD pathway in enteroendocrine cells of the Drosophila anterior midgut.

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

The EIIAGlc amphipathic helix