YtfK activates the stringent response by triggering the alarmone synthetase SpoT in Escherichia coli

Elsa Germain (1) , Paul Guiraud (1) , Deborah Byrne (2) , Badreddine Douzi (1, 3) , Meriem Djendli (1) , Etienne Maisonneuve (1)

1 LCB - Laboratoire de chimie bactérienne
2 IMM - Institut de Microbiologie de la Méditerranée
3 DynAMic - Dynamique des Génomes et Adaptation Microbienne

The stringent response is a general bacterial stress response that allows bacteria to adapt and survive adverse conditions. This reprogramming of cell physiology is caused by the accumulation of the alarmone (p)ppGpp which, in Escherichia coli, depends on the (p)ppGpp synthetase RelA and the bifunctional (p)ppGpp synthetase/hydrolase SpoT. Although conditions that control SpoT-dependent (p)ppGpp accumulation have been described, the molecular mechanisms regulating the switching from (p)ppGpp degradation to synthesis remain poorly understood. Here, we show that the protein YtfK promotes SpoT-dependent accumulation of (p)ppGpp in E. coli and is required for activation of the stringent response during phosphate and fatty acid starvation. Our results indicate that YtfK can interact with SpoT. We propose that YtfK activates the stringent response by tilting the catalytic balance of SpoT toward (p)ppGpp synthesis.

Mots clés: Bacterial physiology; Bacteriology; Microbial genetics

Domaines: Sciences du Vivant [q-bio]

Elsa Germain, Paul Guiraud, Deborah Byrne, Badreddine Douzi, Meriem Djendli, et al.. YtfK activates the stringent response by triggering the alarmone synthetase SpoT in Escherichia coli. Nature Communications, 2019, 10 (1), ⟨10.1038/s41467-019-13764-4⟩. ⟨hal-02446175⟩