TY - JOUR

T1 - (p)ppGpp-mediated stress response induced by defects in outer membrane biogenesis and ATP production promotes survival in Escherichia coli

AU - Roghanian, Mohammad

AU - Semsey, Szabolcs

AU - Løbner-Olesen, Anders

AU - Jalalvand, Farshid

PY - 2019

Y1 - 2019

N2 - Cellular growth requires a high level of coordination to ensure that all processes run in concert. The role of the nucleotide alarmone (p)ppGpp has been extensively studied in response to external stresses, such as amino acid starvation, in Escherichia coli, but much less is known about the involvement of (p)ppGpp in response to perturbations in intracellular processes. We therefore employed CRISPRi to transcriptionally repress essential genes involved in 14 vital processes and investigated whether a (p)ppGpp-mediated response would be induced. We show that (p)ppGpp is produced and required for a pertinent stress response during interference with outer membrane biogenesis and ADP synthesis specifically. When these processes were perturbed via the transcriptional repression of essential genes, wild type E. coli MG1655 ceased growing and entered a semi-dormant state, whereas isogenic (p)ppGpp0 cells continued to grow uncontrollably to the point of lysis. Furthermore, in vivo measurements revealed that the ATP levels were intrinsically offset in (p)ppGpp0 cells, further indicating a role for the alarmone in cellular energy homeostasis. In summary, our investigation suggests that (p)ppGpp acts as a coordinator of cell growth in response to imbalances in outer membrane biogenesis and adenosine ribonucleotide synthesis, elucidating novel roles for (p)ppGpp in bacterial physiology.

AB - Cellular growth requires a high level of coordination to ensure that all processes run in concert. The role of the nucleotide alarmone (p)ppGpp has been extensively studied in response to external stresses, such as amino acid starvation, in Escherichia coli, but much less is known about the involvement of (p)ppGpp in response to perturbations in intracellular processes. We therefore employed CRISPRi to transcriptionally repress essential genes involved in 14 vital processes and investigated whether a (p)ppGpp-mediated response would be induced. We show that (p)ppGpp is produced and required for a pertinent stress response during interference with outer membrane biogenesis and ADP synthesis specifically. When these processes were perturbed via the transcriptional repression of essential genes, wild type E. coli MG1655 ceased growing and entered a semi-dormant state, whereas isogenic (p)ppGpp0 cells continued to grow uncontrollably to the point of lysis. Furthermore, in vivo measurements revealed that the ATP levels were intrinsically offset in (p)ppGpp0 cells, further indicating a role for the alarmone in cellular energy homeostasis. In summary, our investigation suggests that (p)ppGpp acts as a coordinator of cell growth in response to imbalances in outer membrane biogenesis and adenosine ribonucleotide synthesis, elucidating novel roles for (p)ppGpp in bacterial physiology.

U2 - 10.1038/s41598-019-39371-3

DO - 10.1038/s41598-019-39371-3

M3 - Journal article

C2 - 30814571

VL - 9

SP - 1

EP - 11

JO - Scientific Reports

JF - Scientific Reports

SN - 2045-2322

M1 - 2934

ER -