Phosphotransferase-dependent accumulation of (p)ppGpp in response to glutamine deprivation in Caulobacter crescentus.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27109061.
- Also identified by DOI 10.1038/ncomms11423 and PMC identifier 4848567.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
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.
Medical subject headings
- Bacterial Proteins
- Caulobacter crescentus
- Glutamine
- Guanosine Pentaphosphate
- Phosphotransferases