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

Abstract

The V. cholerae phosphoenolpyruvate phosphotransferase system (PTS) is a well-conserved, multicomponent phosphotransfer cascade that regulates cellular physiology and virulence in response to nutritional signals. Glucose-specific enzyme IIA (EIIAGlc), a component of the PTS, is a master regulator that coordinates bacterial metabolism, nutrient uptake, and behavior by direct interactions with protein partners. We show that an amphipathic helix (AH) at the N terminus of V. cholerae EIIAGlc serves as a membrane association domain that is dispensable for interactions with cytoplasmic partners but essential for regulation of integral membrane protein partners. By removing this amphipathic helix, hidden, opposing roles for cytoplasmic partners of EIIAGlc in both biofilm formation and metabolism within the mammalian intestine are revealed. This study defines a novel paradigm for AH function in integrating opposing regulatory functions in the cytoplasm and at the bacterial cell membrane and highlights the PTS as a target for metabolic modulation of the intestinal environment.

Diverse Mechanisms and Circuitry for Global Regulation by the RNA-Binding Protein CsrA

“…Turnover of CsrB/C sRNAs in E. coli is tightly regulated. In addition to the housekeeping endonuclease RNase E and the 3'-5' exonuclease polynucleotide phosphorylase (PNPase), it requires a non-nucleolytic EAL-GGDEF domain-containing protein, CsrD or MshH (Suzuki et al, 2006;Leng et al, 2016;Vijayakumar et al, 2018). Unlike classical EAL-GGDEF domain proteins, CsrD neither synthesizes nor degrades the signaling molecule (3'-5')-cyclic-diguanylate (c-di-GMP).…”

Sequestration of a dual function DNA-binding protein by Vibrio cholerae CRP

“…The aminopeptidase PepA is known to regulate only a few genes directly and participate in site-specific recombination through the formation of hexamers that associate with and bend DNA ( 44 , 47 – 52 ). There are numerous examples of proteins whose activity is modulated by conditional association with the cell membrane ( 33 , 53 – 57 ). We hypothesized that the interaction of PepA and CRP at the cell membrane might modulate their binding to DNA.…”

Proteome and Physiological Characterization of Halotolerant Nodule Endophytes: The Case of Rahnella aquatilis and Serratia plymuthica

“…Among the proteins that were down-regulated under salt stress in Ra4 were: (i) the FliC/FljB family flagellin, whose down-regulation significantly decreased the diameter of the flagella [ 56 ]; (ii) the chemotaxis protein CheW, which is part of the chemotaxis system and allows bacteria to swim towards nutrients and far away from repellants [ 57 ]; (iii) deformylase peptide, cutting the terminal formyl group of proteins, which is lethal for prokaryotes [ 58 ]; (iv) flagellar hook-assembly protein FlgD, a scaffolding protein required for flagellar assembly [ 59 ], and the flagellar hook-associated protein FlgK, essential for the formation and determination of the flagellar filament length [ 60 ]; (v) phosphoenolpyruvate phosphotransferase (PTS) glucose transporter subunit IIA, a system that coordinates the bacterial response to the availability of carbohydrates through direct interactions of its components with protein targets. One of these components, the specific glucose enzyme IIA (EIIAGlc), coordinates bacterial metabolism, nutrient absorption, and interaction with cytoplasmic and membrane proteins [ 61 ].…”