Phosphotransferase-dependent accumulation of (p)ppGpp in response to glutamine deprivation in Caulobacter crescentus.
The alarmone (p)ppGpp is commonly used by bacteria to quickly respond to nutrient starvation. Although (p)ppGpp synthetases such as SpoT have been extensively studied, little is known about the molecular mechanisms stimulating alarmone synthesis upon starvation. Here, we describe an essential role of the nitrogen-related phosphotransferase system (PTS(Ntr)) in controlling (p)ppGpp accumulation in Caulobacter crescentus. We show that cells sense nitrogen starvation by way of detecting glutamine deprivation using the first enzyme (EI(Ntr)) of PTS(Ntr). Decreasing intracellular glutamine concentration triggers phosphorylation of EI(Ntr) and its downstream components HPr and EIIA(Ntr). Once phosphorylated, both HPr∼P and EIIA(Ntr)∼P stimulate (p)ppGpp accumulation by modulating SpoT activities. This burst of second messenger primarily impacts the non-replicative phase of the cell cycle by extending the G1 phase. This work highlights a new role for bacterial PTS systems in stimulating (p)ppGpp accumulation in response to metabolic cues and in controlling cell cycle progression and cell growth.
Bacterial Cell cycle and Development (BCcD), URBM, University of Namur, 61 Rue de Bruxelles, Namur 5000, Belgium.
Séverin
S
Ronneau
Bacterial Cell cycle and Development (BCcD), URBM, University of Namur, 61 Rue de Bruxelles, Namur 5000, Belgium.
Kenny
K
Petit
Bacterial Cell cycle and Development (BCcD), URBM, University of Namur, 61 Rue de Bruxelles, Namur 5000, Belgium.
Xavier
X
De Bolle
Bacterial Cell cycle and Development (BCcD), URBM, University of Namur, 61 Rue de Bruxelles, Namur 5000, Belgium.
Régis
R
Hallez
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016935:Caulobacter crescentus / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D002453:Cell Cycle; D015964:Gene Expression Regulation, Bacterial; D005973:Glutamine / Q000378:metabolism*; D006158:Guanosine Pentaphosphate / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D005973:Glutamine; D006158:Guanosine Pentaphosphate; D010770:Phosphotransferases; D009584:Nitrogen