PoxA, YjeK, and Elongation Factor P Coordinately Modulate Virulence and Drug Resistance in Salmonella enterica

Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
Molecular cell (Impact Factor: 14.02). 07/2010; 39(2):209-21. DOI: 10.1016/j.molcel.2010.06.021
Source: PubMed


We report an interaction between poxA, encoding a paralog of lysyl tRNA-synthetase, and the closely linked yjeK gene, encoding a putative 2,3-beta-lysine aminomutase, that is critical for virulence and stress resistance in Salmonella enterica. Salmonella poxA and yjeK mutants share extensive phenotypic pleiotropy, including attenuated virulence in mice, an increased ability to respire under nutrient-limiting conditions, hypersusceptibility to a variety of diverse growth inhibitors, and altered expression of multiple proteins, including several encoded on the SPI-1 pathogenicity island. PoxA mediates posttranslational modification of bacterial elongation factor P (EF-P), analogous to the modification of the eukaryotic EF-P homolog, eIF5A, with hypusine. The modification of EF-P is a mechanism of regulation whereby PoxA acts as an aminoacyl-tRNA synthetase that attaches an amino acid to a protein resembling tRNA rather than to a tRNA.

Download full-text


Available from: Runjun D Kumar
    • "The bioinformatic identification (Bailly & de Crecy-Lagard, 2010) and experimental validation (Navarre et al., 2010; Yanagisawa et al., 2010) of a post-translational modification system essential for EF-P function in Escherichia coli and Salmonella enterica in 2010 (see also later section on β-lysinylation of EF-P Lys34) laid the basis for unveiling its precise role during protein synthesis three years later. The new insights into the mechanism of EF-P arose through the efforts to discover new regulatory players of the CadABC-module, a lysine-dependent acid-resistance system in E. coli (Fritz et al., 2009) (Fig. 4B). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Translation of polyproline proteins leads to translation arrest. To overcome this ribosome stalling effect, bacteria depend on a specialized translation elongation factor P (EF-P), being orthologous and functional identical to eukaryotic/archaeal elongation factor e/aIF-5A (recently renamed "EF5"). EF-P binds to the stalled ribosome between the peptidyl-tRNA binding and tRNA-exiting sites, and stimulates peptidyl-transferase activity thus allowing translation to resume. In their active form both EF-P and e/aIF-5A are post-translationally modified at a positively charged residue, which protrudes towards the peptidyl-transferase center when bound to the ribosome. While archaeal and eukaryotic IF-5A strictly depend on (deoxy-) hypusination (hypusinylation) of a conserved lysine, bacteria have evolved diverse analogous modification strategies to activate EF-P. In Escherichia coli and Salmonella enterica a lysine is extended by β-lysinylation and subsequently hydroxylated, whereas in Pseudomonas aeruginosa and Shewanella oneidensis an arginine in the equivalent position is rhamnosylated. Inactivation of EF-P, or the corresponding modification systems, reduces not only bacterial fitness but also impairs virulence. Here we review the function of EF-P and IF-5A and their unusual posttranslational protein modifications.
    No preview · Article · Nov 2015 · Molecular Microbiology
  • Source
    • "Like eIF5A, the activity of EF-P is regulated via a post-translational modification. In contrast to eIF5A, EF-P is not hypusinated, but lysinylated by YjeK and YjeA, and finally hydroxylated by YfcM (Bailly and de Crécy-Lagard, 2010; Navarre et al., 2010; Peil et al., 2012). Both eIF5A and EF-P have been shown to be particularly crucial for the synthesis of proteins containing consecutive prolines (Doerfel et al., 2013; Gutierrez et al., 2013; Ude et al., 2013). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The central importance of translational control by posttranslational modification has spurred major interest in regulatory pathways that control translation. One such pathway uniquely adds hypusine to eukaryotic initiation factor 5A (eIF5A), and thereby affects protein synthesis and subsequently cellular proliferation through an unknown mechanism. Using a novel conditional knockout mouse model and a Caenorhabditis elegans knockout model, we found an evolutionarily conserved role for the DOHH-mediated second step of hypusine synthesis in early embryonic development. At the cellular level we observed reduced proliferation and induction of senescence in 3T3 Dohh(-/-) cells as well as reduced capability for malignant transformation. Furthermore, by mass spectrometry we observed that deletion of DOHH results in an unexpected complete loss of hypusine modification. Our results provide new biological insight into the physiological roles of the second step of the hypusination of eIF5A. Moreover, the conditional mouse model presented here provides a powerful tool to manipulate hypusine modification in a temporal and spatial manner, both to analyze how this unique modification normally functions in vivo, as well as how it contributes to different pathological conditions.
    Full-text · Article · May 2014 · Disease Models and Mechanisms
  • Source
    • "Within the E. coli proteome, about 100 proteins possess a polyproline stretch, including the HKs EnvZ and PhoR, as well as the flagella master regulator FlhC. Thus the findings rationalize the motility defects and attenuated virulence exhibited by efp mutants of Salmonella (Navarre et al., 2010). Since the completion of the first bacterial genomesequencing project in 1995 more than 2305 bacterial genomes have been completely sequenced. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Since its inception, Bacterial Locomotion and Signal Transduction (BLAST) meetings have been the place to exchange and share the latest developments in the field of bacterial signal transduction and motility. At the 12th BLAST meeting, held last January in Tucson AZ, researchers from all over the world met to report and discuss progress in diverse aspects of the field. The majority of these advances, however, came at the level of atomic level structures and their associated mechanisms. This was especially true of the biological machines that sense and respond to environmental changes.
    Full-text · Article · Oct 2013 · Molecular Microbiology
Show more