title: Ribosomal dimerization factor YfiA is the major protein synthesized after abrupt glucose depletion in Lactococcus lactis.
abstract: We analysed the response of the model bacterium Lactococcus lactis to abrupt depletion of glucose after several generations of exponential growth. Glucose depletion resulted in a drastic drop in the energy charge accompanied by an extremely low GTP level and an almost total arrest of protein synthesis. Strikingly, the cell prioritized the continued synthesis of a few proteins, of which the ribosomal dimerization factor YfiA was the most highly expressed. Transcriptome analysis showed no immediate decrease in total mRNA levels despite the lowered nucleotide pools and only marginally increased levels of the yfiA transcript. Severe up-regulation of genes in the FruR, CcpA, ArgR and AhrC regulons were consistent with a downshift in carbon and energy source. Based upon the results, we suggest that transcription proceeded long enough to record the transcriptome changes from activation of the FruR, CcpA, ArgR and AhrC regulons, while protein synthesis stopped due to an extremely low GTP concentration emerging a few minutes after glucose depletion. The yfiA deletion mutant exhibited a longer lag phase upon replenishment of glucose and a faster death rate after prolonged starvation supporting that YfiA-mediated ribosomal dimerization is important for keeping long-term starved cells viable and competent for growth initiation.
authors.affiliation: Metabolic Signaling and Regulation Group, DTU Bioengineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
authors.forename: Anne
authors.initials: A
authors.lastname: Breüner
authors.affiliation: Metabolic Signaling and Regulation Group, DTU Bioengineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
authors.forename: Dorte
authors.initials: D
authors.lastname: Frees
authors.affiliation: Metabolic Signaling and Regulation Group, DTU Bioengineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
authors.forename: Pekka
authors.initials: P
authors.lastname: Varmanen
authors.affiliation: Metabolic Signaling and Regulation Group, DTU Bioengineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
authors.forename: Anna Monika
authors.initials: AM
authors.lastname: Boguta
authors.affiliation: Metabolic Signaling and Regulation Group, DTU Bioengineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
authors.forename: Karin
authors.initials: K
authors.lastname: Hammer
authors.affiliation: Metabolic Signaling and Regulation Group, DTU Bioengineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
authors.forename: Jan
authors.initials: J
authors.lastname: Martinussen
authors.affiliation: Metabolic Signaling and Regulation Group, DTU Bioengineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
authors.forename: Mogens
authors.initials: M
authors.lastname: Kilstrup
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D019281:Dimerization; D005947:Glucose / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D013294:Lactococcus lactis / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D014176:Protein Biosynthesis; D012269:Ribosomal Proteins / Q000235:genetics* / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D012269:Ribosomal Proteins; C499682:YfiA protein, bacteria; D006160:Guanosine Triphosphate; D005947:Glucose