title: HipA-triggered growth arrest and β-lactam tolerance in Escherichia coli are mediated by RelA-dependent ppGpp synthesis.
abstract: Persistence is a phenomenon whereby a subpopulation of bacterial cells enters a transient growth-arrested state that confers antibiotic tolerance. While entrance into persistence has been linked to the activities of toxin proteins, the molecular mechanisms by which toxins induce growth arrest and the persistent state remain unclear. Here, we show that overexpression of the protein kinase HipA in Escherichia coli triggers growth arrest by activating synthesis of the alarmone guanosine tetraphosphate (ppGpp) by the enzyme RelA, a signal typically associated with amino acid starvation. We further demonstrate that chemically suppressing ppGpp synthesis with chloramphenicol relieves inhibition of DNA replication initiation and RNA synthesis in HipA-arrested cells and restores vulnerability to β-lactam antibiotics. HipA-arrested cells maintain glucose uptake and oxygen consumption and accumulate amino acids as a consequence of translational inhibition. We harness the active metabolism of HipA-arrested cells to provide a bacteriophage-resistant platform for the production of biotechnologically relevant compounds, which may represent an innovative solution to the costly problem of phage contamination in industrial fermentations.
authors.affiliation: Joint BioEnergy Institute, Emeryville, CA, USA. gebokinsky@lbl.gov
authors.forename: Gregory
authors.initials: G
authors.lastname: Bokinsky
authors.forename: Edward E K
authors.initials: EE
authors.lastname: Baidoo
authors.forename: Swetha
authors.initials: S
authors.lastname: Akella
authors.forename: Helcio
authors.initials: H
authors.lastname: Burd
authors.forename: Daniel
authors.initials: D
authors.lastname: Weaver
authors.forename: Jorge
authors.initials: J
authors.lastname: Alonso-Gutierrez
authors.forename: Héctor
authors.initials: H
authors.lastname: García-Martín
authors.forename: Taek Soon
authors.initials: TS
authors.lastname: Lee
authors.forename: Jay D
authors.initials: JD
authors.lastname: Keasling
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000378:metabolism; D008025:Ligases / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D047090:beta-Lactams / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D047090:beta-Lactams; C070741:hipA protein, E coli; D008025:Ligases; C028812:guanosine 3',5'-polyphosphate synthetases; D005947:Glucose; D010100:Oxygen