TY  - JOUR
AU  - Engl, Christoph
AU  - Jovanović, Goran
AU  - Brackston, Rowan D.
AU  - Kotta-Loizou, Ioly
AU  - Buck, Martin
PY  - 2020
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/1323
AB  - Transcription is fundamentally noisy, leading to significant heterogeneity across bacterial populations. Noise is often attributed to burstiness, but the underlying mechanisms and their dependence on the mode of promotor regulation remain unclear. Here, we measure E. coli single cell mRNA levels for two stress responses that depend on bacterial sigma factors with different mode of transcription initiation (sigma (70) and sigma (54)). By fitting a stochastic model to the observed mRNA distributions, we show that the transition from low to high expression of the sigma (70)-controlled stress response is regulated via the burst size, while that of the sigma (54)-controlled stress response is regulated via the burst frequency. Therefore, transcription initiation involving sigma (54) differs from other bacterial systems, and yields bursting kinetics characteristic of eukaryotic systems. Transcription noise in bacteria is often attributed to burstiness, but the mechanisms are unclear. Here, the authors show that the transition from low to high expression can be regulated via burst size or burst frequency, depending on the mode of transcription initiation determined by different sigma factors.
PB  - Nature Publishing Group, London
T2  - Nature Communications
T1  - The route to transcription initiation determines the mode of transcriptional bursting in E. coli
IS  - 1
VL  - 11
DO  - 10.1038/s41467-020-16367-6
ER  - 

@article{
author = "Engl, Christoph and Jovanović, Goran and Brackston, Rowan D. and Kotta-Loizou, Ioly and Buck, Martin",
year = "2020",
abstract = "Transcription is fundamentally noisy, leading to significant heterogeneity across bacterial populations. Noise is often attributed to burstiness, but the underlying mechanisms and their dependence on the mode of promotor regulation remain unclear. Here, we measure E. coli single cell mRNA levels for two stress responses that depend on bacterial sigma factors with different mode of transcription initiation (sigma (70) and sigma (54)). By fitting a stochastic model to the observed mRNA distributions, we show that the transition from low to high expression of the sigma (70)-controlled stress response is regulated via the burst size, while that of the sigma (54)-controlled stress response is regulated via the burst frequency. Therefore, transcription initiation involving sigma (54) differs from other bacterial systems, and yields bursting kinetics characteristic of eukaryotic systems. Transcription noise in bacteria is often attributed to burstiness, but the mechanisms are unclear. Here, the authors show that the transition from low to high expression can be regulated via burst size or burst frequency, depending on the mode of transcription initiation determined by different sigma factors.",
publisher = "Nature Publishing Group, London",
journal = "Nature Communications",
title = "The route to transcription initiation determines the mode of transcriptional bursting in E. coli",
number = "1",
volume = "11",
doi = "10.1038/s41467-020-16367-6"
}

Engl, C., Jovanović, G., Brackston, R. D., Kotta-Loizou, I.,& Buck, M.. (2020). The route to transcription initiation determines the mode of transcriptional bursting in E. coli. in Nature Communications
Nature Publishing Group, London., 11(1).
https://doi.org/10.1038/s41467-020-16367-6

Engl C, Jovanović G, Brackston RD, Kotta-Loizou I, Buck M. The route to transcription initiation determines the mode of transcriptional bursting in E. coli. in Nature Communications. 2020;11(1).
doi:10.1038/s41467-020-16367-6 .

Engl, Christoph, Jovanović, Goran, Brackston, Rowan D., Kotta-Loizou, Ioly, Buck, Martin, "The route to transcription initiation determines the mode of transcriptional bursting in E. coli" in Nature Communications, 11, no. 1 (2020),
https://doi.org/10.1038/s41467-020-16367-6 . .

TY  - JOUR
AU  - McDonald, Christopher
AU  - Jovanović, Goran
AU  - Wallace, B. A.
AU  - Ces, Oscar
AU  - Buck, Martin
PY  - 2017
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/1067
AB  - The phage shock protein (Psp) response maintains integrity of the inner membrane (IM) in response to extracytoplasmic stress conditions and is widely distributed amongst enterobacteria. Its central component PspA, a member of the IM30 peripheral membrane protein family, acts as a major effector of the system through its direct association with the IM. Under non-stress conditions PspA also negatively regulates its own expression via direct interaction with the AAA+ ATPase PspF. PspA has a counterpart in cyanobacteria called Vipp1, which is implicated in protection of the thylakoid membranes. PspA's and Vipp1's conserved N-terminal regions contain a putative amphipathic helix a (AHa) required for membrane binding. An adjacent amphipathic helix b (AHb) in PspA is required for imposing negative control upon PspF. Here, purified peptides derived from the putative AH regions of PspA and Vipp1 were used to directly probe their effector and regulatory functions. We observed direct membrane-binding of AHa derived peptides and an accompanying change in secondary structure from unstructured to alpha-helical establishing them as bona fide membrane-sensing AH's. The peptide-binding specificities and their effects on membrane stability depend on membrane anionic lipid content and stored curvature elastic stress, in agreement with full length PspA and Vipp1 protein functionalities. AHb of PspA inhibited the ATPase activity of PspF demonstrating its direct regulatory role. These findings provide new insight into the membrane binding and function of PspA and Vipp1 and establish that synthetic peptides can be used to probe the structure-function of the IM30 protein family.
PB  - Elsevier Science Bv, Amsterdam
T2  - Biochimica Et Biophysica Acta-Biomembranes
T1  - Structure and function of PspA and Vipp1 N-terminal peptides: Insights into the membrane stress sensing and mitigation
EP  - 39
IS  - 1
SP  - 28
VL  - 1859
DO  - 10.1016/j.bbamem.2016.10.018
ER  - 

@article{
author = "McDonald, Christopher and Jovanović, Goran and Wallace, B. A. and Ces, Oscar and Buck, Martin",
year = "2017",
abstract = "The phage shock protein (Psp) response maintains integrity of the inner membrane (IM) in response to extracytoplasmic stress conditions and is widely distributed amongst enterobacteria. Its central component PspA, a member of the IM30 peripheral membrane protein family, acts as a major effector of the system through its direct association with the IM. Under non-stress conditions PspA also negatively regulates its own expression via direct interaction with the AAA+ ATPase PspF. PspA has a counterpart in cyanobacteria called Vipp1, which is implicated in protection of the thylakoid membranes. PspA's and Vipp1's conserved N-terminal regions contain a putative amphipathic helix a (AHa) required for membrane binding. An adjacent amphipathic helix b (AHb) in PspA is required for imposing negative control upon PspF. Here, purified peptides derived from the putative AH regions of PspA and Vipp1 were used to directly probe their effector and regulatory functions. We observed direct membrane-binding of AHa derived peptides and an accompanying change in secondary structure from unstructured to alpha-helical establishing them as bona fide membrane-sensing AH's. The peptide-binding specificities and their effects on membrane stability depend on membrane anionic lipid content and stored curvature elastic stress, in agreement with full length PspA and Vipp1 protein functionalities. AHb of PspA inhibited the ATPase activity of PspF demonstrating its direct regulatory role. These findings provide new insight into the membrane binding and function of PspA and Vipp1 and establish that synthetic peptides can be used to probe the structure-function of the IM30 protein family.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Biochimica Et Biophysica Acta-Biomembranes",
title = "Structure and function of PspA and Vipp1 N-terminal peptides: Insights into the membrane stress sensing and mitigation",
pages = "39-28",
number = "1",
volume = "1859",
doi = "10.1016/j.bbamem.2016.10.018"
}

McDonald, C., Jovanović, G., Wallace, B. A., Ces, O.,& Buck, M.. (2017). Structure and function of PspA and Vipp1 N-terminal peptides: Insights into the membrane stress sensing and mitigation. in Biochimica Et Biophysica Acta-Biomembranes
Elsevier Science Bv, Amsterdam., 1859(1), 28-39.
https://doi.org/10.1016/j.bbamem.2016.10.018

McDonald C, Jovanović G, Wallace BA, Ces O, Buck M. Structure and function of PspA and Vipp1 N-terminal peptides: Insights into the membrane stress sensing and mitigation. in Biochimica Et Biophysica Acta-Biomembranes. 2017;1859(1):28-39.
doi:10.1016/j.bbamem.2016.10.018 .

McDonald, Christopher, Jovanović, Goran, Wallace, B. A., Ces, Oscar, Buck, Martin, "Structure and function of PspA and Vipp1 N-terminal peptides: Insights into the membrane stress sensing and mitigation" in Biochimica Et Biophysica Acta-Biomembranes, 1859, no. 1 (2017):28-39,
https://doi.org/10.1016/j.bbamem.2016.10.018 . .

TY  - CHAP
AU  - Zhang, Nan
AU  - Jovanović, Goran
AU  - McDonald, Christopher
AU  - Ces, Oscar
AU  - Zhang, Xiaodong
AU  - Buck, Martin
PY  - 2016
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/917
AB  - Transcription regulation in a temporal and conditional manner underpins the lifecycle of enterobacterial pathogens. Upon exposure to a wide array of environmental cues, these pathogens modulate their gene expression via the RNA polymerase and associated sigma factors. Different sigma factors, either involved in general 'house-keeping' or specific responses, guide the RNA polymerase to their cognate promoter DNAs. The major alternative sigma54 factor when activated helps pathogens manage stresses and proliferate in their ecological niches. In this chapter, we review the function and regulation of the sigma54-dependent Phage shock protein (Psp) system-a major stress response when Gram-negative pathogens encounter damages to their inner membranes. We discuss the recent development on mechanisms of gene regulation, signal transduction and stress mitigation in light of different biophysical and biochemical approaches.
PB  - Springer-Verlag Berlin, Berlin
T2  - Biophysics of Infection
T1  - Transcription Regulation and Membrane Stress Management in Enterobacterial Pathogens
EP  - 230
SP  - 207
VL  - 915
DO  - 10.1007/978-3-319-32189-9_13
ER  - 

@inbook{
author = "Zhang, Nan and Jovanović, Goran and McDonald, Christopher and Ces, Oscar and Zhang, Xiaodong and Buck, Martin",
year = "2016",
abstract = "Transcription regulation in a temporal and conditional manner underpins the lifecycle of enterobacterial pathogens. Upon exposure to a wide array of environmental cues, these pathogens modulate their gene expression via the RNA polymerase and associated sigma factors. Different sigma factors, either involved in general 'house-keeping' or specific responses, guide the RNA polymerase to their cognate promoter DNAs. The major alternative sigma54 factor when activated helps pathogens manage stresses and proliferate in their ecological niches. In this chapter, we review the function and regulation of the sigma54-dependent Phage shock protein (Psp) system-a major stress response when Gram-negative pathogens encounter damages to their inner membranes. We discuss the recent development on mechanisms of gene regulation, signal transduction and stress mitigation in light of different biophysical and biochemical approaches.",
publisher = "Springer-Verlag Berlin, Berlin",
journal = "Biophysics of Infection",
booktitle = "Transcription Regulation and Membrane Stress Management in Enterobacterial Pathogens",
pages = "230-207",
volume = "915",
doi = "10.1007/978-3-319-32189-9_13"
}

Zhang, N., Jovanović, G., McDonald, C., Ces, O., Zhang, X.,& Buck, M.. (2016). Transcription Regulation and Membrane Stress Management in Enterobacterial Pathogens. in Biophysics of Infection
Springer-Verlag Berlin, Berlin., 915, 207-230.
https://doi.org/10.1007/978-3-319-32189-9_13

Zhang N, Jovanović G, McDonald C, Ces O, Zhang X, Buck M. Transcription Regulation and Membrane Stress Management in Enterobacterial Pathogens. in Biophysics of Infection. 2016;915:207-230.
doi:10.1007/978-3-319-32189-9_13 .

Zhang, Nan, Jovanović, Goran, McDonald, Christopher, Ces, Oscar, Zhang, Xiaodong, Buck, Martin, "Transcription Regulation and Membrane Stress Management in Enterobacterial Pathogens" in Biophysics of Infection, 915 (2016):207-230,
https://doi.org/10.1007/978-3-319-32189-9_13 . .

TY  - JOUR
AU  - Schaefer, Jorrit
AU  - Jovanović, Goran
AU  - Kotta-Loizou, Loly
AU  - Buck, Martin
PY  - 2016
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/935
AB  - Historically, the lacZ gene is one of the most universally used reporters of gene expression in molecular biology. Its activity can be quantified using an artificial substrate, o-nitrophenyl-ss-D-galactopyranoside (ONPG). However, the traditional method for measuring LacZ activity (first described by J. H. Miller in 1972) can be challenging for a large number of samples, is prone to variability, and involves hazardous compounds for lysis (e.g., chloroform, toluene). Here we describe a single-step assay using a 96-well microplate reader with a proven alternative cell permeabilization method. This modified protocol reduces handling time by 90%.
PB  - Academic Press Inc Elsevier Science, San Diego
T2  - Analytical Biochemistry
T1  - Single-step method for beta-galactosidase assays in Escherichia coli using a 96-well microplate reader
EP  - 57
SP  - 56
VL  - 503
DO  - 10.1016/j.ab.2016.03.017
ER  - 

@article{
author = "Schaefer, Jorrit and Jovanović, Goran and Kotta-Loizou, Loly and Buck, Martin",
year = "2016",
abstract = "Historically, the lacZ gene is one of the most universally used reporters of gene expression in molecular biology. Its activity can be quantified using an artificial substrate, o-nitrophenyl-ss-D-galactopyranoside (ONPG). However, the traditional method for measuring LacZ activity (first described by J. H. Miller in 1972) can be challenging for a large number of samples, is prone to variability, and involves hazardous compounds for lysis (e.g., chloroform, toluene). Here we describe a single-step assay using a 96-well microplate reader with a proven alternative cell permeabilization method. This modified protocol reduces handling time by 90%.",
publisher = "Academic Press Inc Elsevier Science, San Diego",
journal = "Analytical Biochemistry",
title = "Single-step method for beta-galactosidase assays in Escherichia coli using a 96-well microplate reader",
pages = "57-56",
volume = "503",
doi = "10.1016/j.ab.2016.03.017"
}

Schaefer, J., Jovanović, G., Kotta-Loizou, L.,& Buck, M.. (2016). Single-step method for beta-galactosidase assays in Escherichia coli using a 96-well microplate reader. in Analytical Biochemistry
Academic Press Inc Elsevier Science, San Diego., 503, 56-57.
https://doi.org/10.1016/j.ab.2016.03.017

Schaefer J, Jovanović G, Kotta-Loizou L, Buck M. Single-step method for beta-galactosidase assays in Escherichia coli using a 96-well microplate reader. in Analytical Biochemistry. 2016;503:56-57.
doi:10.1016/j.ab.2016.03.017 .

Schaefer, Jorrit, Jovanović, Goran, Kotta-Loizou, Loly, Buck, Martin, "Single-step method for beta-galactosidase assays in Escherichia coli using a 96-well microplate reader" in Analytical Biochemistry, 503 (2016):56-57,
https://doi.org/10.1016/j.ab.2016.03.017 . .

TY  - JOUR
AU  - Mehta, Parul
AU  - Jovanović, Goran
AU  - Ying, Liming
AU  - Buck, Martin
PY  - 2015
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/881
AB  - The bacterial cell envelope retains a highly dense cytoplasm. The properties of the cytoplasm change with the metabolic state of the cell, the logarithmic phase (log) being highly active and the stationary phase metabolically much slower. Under the differing growth phases, many different types of stress mechanisms are activated in order to maintain cellular integrity. One such response in enterobacteria is the phage shock protein (Psp) response that enables adaptation to the inner membrane (IM) stress. The Psp system consists of a transcriptional activator PspF, negative regulator PspA, signal sensors PspBC, with PspA and PspG acting as effectors. The single molecule imaging of the PspF showed the existence of dynamic communication between the nucleoid-bound states of PspF and membrane via negative regulator PspA and PspBC sensors. The movement of proteins in the cytoplasm of bacterial cells is often by passive diffusion. It is plausible that the dynamics of the biomolecules differs with the state of the cytoplasm depending on the growth phase. Therefore, the Psp response proteins might encounter the densely packed glass-like properties of the cytoplasm in the stationary phase, which can influence their cellular dynamics and function. By comparing the properties of the log and stationary phases, we find that the dynamics of PspF are influenced by the growth phase and may be controlled by the changes in the cytoplasmic fluidity.
PB  - Portland Press Ltd, London
T2  - Biochemical Society Transactions
T1  - Is the cellular and molecular machinery docile in the stationary phase of Escherichia coli?
EP  - 171
SP  - 168
VL  - 43
DO  - 10.1042/BST20140267
ER  - 

@article{
author = "Mehta, Parul and Jovanović, Goran and Ying, Liming and Buck, Martin",
year = "2015",
abstract = "The bacterial cell envelope retains a highly dense cytoplasm. The properties of the cytoplasm change with the metabolic state of the cell, the logarithmic phase (log) being highly active and the stationary phase metabolically much slower. Under the differing growth phases, many different types of stress mechanisms are activated in order to maintain cellular integrity. One such response in enterobacteria is the phage shock protein (Psp) response that enables adaptation to the inner membrane (IM) stress. The Psp system consists of a transcriptional activator PspF, negative regulator PspA, signal sensors PspBC, with PspA and PspG acting as effectors. The single molecule imaging of the PspF showed the existence of dynamic communication between the nucleoid-bound states of PspF and membrane via negative regulator PspA and PspBC sensors. The movement of proteins in the cytoplasm of bacterial cells is often by passive diffusion. It is plausible that the dynamics of the biomolecules differs with the state of the cytoplasm depending on the growth phase. Therefore, the Psp response proteins might encounter the densely packed glass-like properties of the cytoplasm in the stationary phase, which can influence their cellular dynamics and function. By comparing the properties of the log and stationary phases, we find that the dynamics of PspF are influenced by the growth phase and may be controlled by the changes in the cytoplasmic fluidity.",
publisher = "Portland Press Ltd, London",
journal = "Biochemical Society Transactions",
title = "Is the cellular and molecular machinery docile in the stationary phase of Escherichia coli?",
pages = "171-168",
volume = "43",
doi = "10.1042/BST20140267"
}

Mehta, P., Jovanović, G., Ying, L.,& Buck, M.. (2015). Is the cellular and molecular machinery docile in the stationary phase of Escherichia coli?. in Biochemical Society Transactions
Portland Press Ltd, London., 43, 168-171.
https://doi.org/10.1042/BST20140267

Mehta P, Jovanović G, Ying L, Buck M. Is the cellular and molecular machinery docile in the stationary phase of Escherichia coli?. in Biochemical Society Transactions. 2015;43:168-171.
doi:10.1042/BST20140267 .

Mehta, Parul, Jovanović, Goran, Ying, Liming, Buck, Martin, "Is the cellular and molecular machinery docile in the stationary phase of Escherichia coli?" in Biochemical Society Transactions, 43 (2015):168-171,
https://doi.org/10.1042/BST20140267 . .

TY  - JOUR
AU  - Jovanović, Goran
AU  - Sheng, Xia
AU  - Ale, Angelique
AU  - Feliu, Elisenda
AU  - Harrington, Heather A.
AU  - Kirk, Paul
AU  - Wiuf, Carsten
AU  - Buck, Martin
AU  - Stumpf, Michael P. H.
PY  - 2015
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/885
AB  - Two-component systems play a central part in bacterial signal transduction. Phosphorelay mechanisms have been linked to more robust and ultra-sensitive signalling dynamics. The molecular machinery that facilitates such a signalling is, however, only understood in outline. In particular the functional relevance of the dimerization of a non-orthodox or hybrid histidine kinase along which the phosphorelay takes place has been a subject of debate. We use a combination of molecular and genetic approaches, coupled to mathematical and statistical modelling, to demonstrate that the different possible intra- and inter-molecular mechanisms of phosphotransfer are formally non-identifiable in Escherichia coli expressing the ArcB non-orthodox histidine kinase used in anoxic redox control. In order to resolve this issue we further analyse the mathematical model in order to identify discriminatory experiments, which are then performed to address cis- and trans-phosphorelay mechanisms. The results suggest that exclusive cis- and trans-mechanisms will not be operating, instead the functional phosphorelay is likely to build around a sequence of allosteric interactions among the domain pairs in the histidine kinase. This is the first detailed mechanistic analysis of the molecular processes involved in non-orthodox two-component signalling and our results suggest strongly that dimerization facilitates more discriminatory proof-reading of external signals, via these allosteric reactions, prior to them being further processed.
PB  - Royal Soc Chemistry, Cambridge
T2  - Molecular Biosystems
T1  - Phosphorelay of non-orthodox two component systems functions through a bi-molecular mechanism in vivo: the case of ArcB
EP  - 1359
IS  - 5
SP  - 1348
VL  - 11
DO  - 10.1039/c4mb00720d
ER  - 

@article{
author = "Jovanović, Goran and Sheng, Xia and Ale, Angelique and Feliu, Elisenda and Harrington, Heather A. and Kirk, Paul and Wiuf, Carsten and Buck, Martin and Stumpf, Michael P. H.",
year = "2015",
abstract = "Two-component systems play a central part in bacterial signal transduction. Phosphorelay mechanisms have been linked to more robust and ultra-sensitive signalling dynamics. The molecular machinery that facilitates such a signalling is, however, only understood in outline. In particular the functional relevance of the dimerization of a non-orthodox or hybrid histidine kinase along which the phosphorelay takes place has been a subject of debate. We use a combination of molecular and genetic approaches, coupled to mathematical and statistical modelling, to demonstrate that the different possible intra- and inter-molecular mechanisms of phosphotransfer are formally non-identifiable in Escherichia coli expressing the ArcB non-orthodox histidine kinase used in anoxic redox control. In order to resolve this issue we further analyse the mathematical model in order to identify discriminatory experiments, which are then performed to address cis- and trans-phosphorelay mechanisms. The results suggest that exclusive cis- and trans-mechanisms will not be operating, instead the functional phosphorelay is likely to build around a sequence of allosteric interactions among the domain pairs in the histidine kinase. This is the first detailed mechanistic analysis of the molecular processes involved in non-orthodox two-component signalling and our results suggest strongly that dimerization facilitates more discriminatory proof-reading of external signals, via these allosteric reactions, prior to them being further processed.",
publisher = "Royal Soc Chemistry, Cambridge",
journal = "Molecular Biosystems",
title = "Phosphorelay of non-orthodox two component systems functions through a bi-molecular mechanism in vivo: the case of ArcB",
pages = "1359-1348",
number = "5",
volume = "11",
doi = "10.1039/c4mb00720d"
}

Jovanović, G., Sheng, X., Ale, A., Feliu, E., Harrington, H. A., Kirk, P., Wiuf, C., Buck, M.,& Stumpf, M. P. H.. (2015). Phosphorelay of non-orthodox two component systems functions through a bi-molecular mechanism in vivo: the case of ArcB. in Molecular Biosystems
Royal Soc Chemistry, Cambridge., 11(5), 1348-1359.
https://doi.org/10.1039/c4mb00720d

Jovanović G, Sheng X, Ale A, Feliu E, Harrington HA, Kirk P, Wiuf C, Buck M, Stumpf MPH. Phosphorelay of non-orthodox two component systems functions through a bi-molecular mechanism in vivo: the case of ArcB. in Molecular Biosystems. 2015;11(5):1348-1359.
doi:10.1039/c4mb00720d .

Jovanović, Goran, Sheng, Xia, Ale, Angelique, Feliu, Elisenda, Harrington, Heather A., Kirk, Paul, Wiuf, Carsten, Buck, Martin, Stumpf, Michael P. H., "Phosphorelay of non-orthodox two component systems functions through a bi-molecular mechanism in vivo: the case of ArcB" in Molecular Biosystems, 11, no. 5 (2015):1348-1359,
https://doi.org/10.1039/c4mb00720d . .

TY  - JOUR
AU  - McDonald, Christopher
AU  - Jovanović, Goran
AU  - Ces, Oscar
AU  - Buck, Martin
PY  - 2015
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/838
AB  - Phage shock protein A (PspA), which is responsible for maintaining inner membrane integrity under stress in enterobacteria, and vesicle-inducting protein in plastids 1 (Vipp1), which functions for membrane maintenance and thylakoid biogenesis in cyanobacteria and plants, are similar peripheral membrane-binding proteins. Their homologous N-terminal amphipathic helices are required for membrane binding; however, the membrane features recognized and required for expressing their functionalities have remained largely uncharacterized. Rigorously controlled, in vitro methodologies with lipid vesicles and purified proteins were used in this study and provided the first biochemical and biophysical characterizations of membrane binding by PspA and Vipp1. Both proteins are found to sense stored curvature elastic (SCE) stress and anionic lipids within the membrane. PspA has an enhanced sensitivity for SCE stress and a higher affinity for the membrane than Vipp1. These variations in binding may be crucial for some of the proteins' differing roles in vivo. Assays probing the transcriptional regulatory function of PspA in the presence of vesicles showed that a relief of transcription inhibition occurs in an SCE stress-specific manner. This in vitro recapitulation of membrane stress-dependent transcription control suggests that the Psp response may be mounted in vivo when a cell's inner membrane experiences increased SCE stress. IMPORTANCE All cell types maintain the integrity of their membrane systems. One widely distributed membrane stress response system in bacteria is the phage shock protein (Psp) system. The central component, peripheral membrane protein PspA, which mitigates inner membrane stress in bacteria, has a counterpart, Vipp1, which functions for membrane maintenance and thylakoid biogenesis in plants and photosynthetic bacteria. Membrane association of both these proteins is accepted as playing a pivotal role in their functions. Here we show that direct membrane binding by PspA and Vipp1 is driven by two physio-chemical signals, one of which is membrane stress specific. Our work points to alleviation of membrane stored curvature elastic stress by amphipathic helix insertions as an attractive mechanism for membrane maintenance by PspA and Vipp1. Furthermore, the identification of a physical, stress-related membrane signal suggests a unilateral mechanism that promotes both binding of PspA and induction of the Psp response.
PB  - Amer Soc Microbiology, Washington
T2  - MBIO
T1  - Membrane Stored Curvature Elastic Stress Modulates Recruitment of Maintenance Proteins PspA and Vipp1
IS  - 5
VL  - 6
DO  - 10.1128/mBio.01188-15
ER  - 

@article{
author = "McDonald, Christopher and Jovanović, Goran and Ces, Oscar and Buck, Martin",
year = "2015",
abstract = "Phage shock protein A (PspA), which is responsible for maintaining inner membrane integrity under stress in enterobacteria, and vesicle-inducting protein in plastids 1 (Vipp1), which functions for membrane maintenance and thylakoid biogenesis in cyanobacteria and plants, are similar peripheral membrane-binding proteins. Their homologous N-terminal amphipathic helices are required for membrane binding; however, the membrane features recognized and required for expressing their functionalities have remained largely uncharacterized. Rigorously controlled, in vitro methodologies with lipid vesicles and purified proteins were used in this study and provided the first biochemical and biophysical characterizations of membrane binding by PspA and Vipp1. Both proteins are found to sense stored curvature elastic (SCE) stress and anionic lipids within the membrane. PspA has an enhanced sensitivity for SCE stress and a higher affinity for the membrane than Vipp1. These variations in binding may be crucial for some of the proteins' differing roles in vivo. Assays probing the transcriptional regulatory function of PspA in the presence of vesicles showed that a relief of transcription inhibition occurs in an SCE stress-specific manner. This in vitro recapitulation of membrane stress-dependent transcription control suggests that the Psp response may be mounted in vivo when a cell's inner membrane experiences increased SCE stress. IMPORTANCE All cell types maintain the integrity of their membrane systems. One widely distributed membrane stress response system in bacteria is the phage shock protein (Psp) system. The central component, peripheral membrane protein PspA, which mitigates inner membrane stress in bacteria, has a counterpart, Vipp1, which functions for membrane maintenance and thylakoid biogenesis in plants and photosynthetic bacteria. Membrane association of both these proteins is accepted as playing a pivotal role in their functions. Here we show that direct membrane binding by PspA and Vipp1 is driven by two physio-chemical signals, one of which is membrane stress specific. Our work points to alleviation of membrane stored curvature elastic stress by amphipathic helix insertions as an attractive mechanism for membrane maintenance by PspA and Vipp1. Furthermore, the identification of a physical, stress-related membrane signal suggests a unilateral mechanism that promotes both binding of PspA and induction of the Psp response.",
publisher = "Amer Soc Microbiology, Washington",
journal = "MBIO",
title = "Membrane Stored Curvature Elastic Stress Modulates Recruitment of Maintenance Proteins PspA and Vipp1",
number = "5",
volume = "6",
doi = "10.1128/mBio.01188-15"
}

McDonald, C., Jovanović, G., Ces, O.,& Buck, M.. (2015). Membrane Stored Curvature Elastic Stress Modulates Recruitment of Maintenance Proteins PspA and Vipp1. in MBIO
Amer Soc Microbiology, Washington., 6(5).
https://doi.org/10.1128/mBio.01188-15

McDonald C, Jovanović G, Ces O, Buck M. Membrane Stored Curvature Elastic Stress Modulates Recruitment of Maintenance Proteins PspA and Vipp1. in MBIO. 2015;6(5).
doi:10.1128/mBio.01188-15 .

McDonald, Christopher, Jovanović, Goran, Ces, Oscar, Buck, Martin, "Membrane Stored Curvature Elastic Stress Modulates Recruitment of Maintenance Proteins PspA and Vipp1" in MBIO, 6, no. 5 (2015),
https://doi.org/10.1128/mBio.01188-15 . .

TY  - JOUR
AU  - Jovanović, Goran
AU  - Mehta, Parul
AU  - McDonald, Christopher
AU  - Davidson, Anthony C.
AU  - Uzdavinys, Povilas
AU  - Ying, Liming
AU  - Buck, Martin
PY  - 2014
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/782
AB  - The phage shock protein (Psp) systems found in bacteria, archaea and higher plants respond to extracytoplasmic stresses that damage the cytoplasmic membrane and enable cells to repair their membranes. The conserved membrane-associated effector protein PspA has four a-helical domains (HD1- HD4) and helps to repair the membrane as a high-order oligomer. In enterobacteria, under non-stress conditions, PspA as a low-order assembly directly inhibits its cognate transcription activator PspF. Here we show that N-terminal amphipathic helices ahA and ahB in PspA HD1 are functional determinants involved in negative gene control and stress signal perception and its transduction via interactions with the PspBC membrane stress sensors and the inner membrane (IM). The amphipathic helices enable PspA to switch from a low-order gene regulator into an IM-bound high-order effector complex under membrane stress. Conserved residue proline 25 is involved in sequential use of the amphipathic helices and ahA IM interaction. Single molecule imaging of eGFP-PspA and its amphipathic helices variants in live Escherichia coli cells show distinct spatial and temporal organisations of PspA corresponding to its negative control and effector functions. These findings inform studies on the role of the Psp system in persister cell formation and cell envelope protection in bacterial pathogens and provide a basis for exploring the specialised roles of PspA homologues such as YjfJ, LiaH and Vipp1.
PB  - Academic Press Ltd- Elsevier Science Ltd, London
T2  - Journal of Molecular Biology
T1  - The N-Terminal Amphipathic Helices Determine Regulatory and Effector Functions of Phage Shock Protein A (PspA) in Escherichia coli
EP  - 1511
IS  - 7
SP  - 1498
VL  - 426
DO  - 10.1016/j.jmb.2013.12.016
ER  - 

@article{
author = "Jovanović, Goran and Mehta, Parul and McDonald, Christopher and Davidson, Anthony C. and Uzdavinys, Povilas and Ying, Liming and Buck, Martin",
year = "2014",
abstract = "The phage shock protein (Psp) systems found in bacteria, archaea and higher plants respond to extracytoplasmic stresses that damage the cytoplasmic membrane and enable cells to repair their membranes. The conserved membrane-associated effector protein PspA has four a-helical domains (HD1- HD4) and helps to repair the membrane as a high-order oligomer. In enterobacteria, under non-stress conditions, PspA as a low-order assembly directly inhibits its cognate transcription activator PspF. Here we show that N-terminal amphipathic helices ahA and ahB in PspA HD1 are functional determinants involved in negative gene control and stress signal perception and its transduction via interactions with the PspBC membrane stress sensors and the inner membrane (IM). The amphipathic helices enable PspA to switch from a low-order gene regulator into an IM-bound high-order effector complex under membrane stress. Conserved residue proline 25 is involved in sequential use of the amphipathic helices and ahA IM interaction. Single molecule imaging of eGFP-PspA and its amphipathic helices variants in live Escherichia coli cells show distinct spatial and temporal organisations of PspA corresponding to its negative control and effector functions. These findings inform studies on the role of the Psp system in persister cell formation and cell envelope protection in bacterial pathogens and provide a basis for exploring the specialised roles of PspA homologues such as YjfJ, LiaH and Vipp1.",
publisher = "Academic Press Ltd- Elsevier Science Ltd, London",
journal = "Journal of Molecular Biology",
title = "The N-Terminal Amphipathic Helices Determine Regulatory and Effector Functions of Phage Shock Protein A (PspA) in Escherichia coli",
pages = "1511-1498",
number = "7",
volume = "426",
doi = "10.1016/j.jmb.2013.12.016"
}

Jovanović, G., Mehta, P., McDonald, C., Davidson, A. C., Uzdavinys, P., Ying, L.,& Buck, M.. (2014). The N-Terminal Amphipathic Helices Determine Regulatory and Effector Functions of Phage Shock Protein A (PspA) in Escherichia coli. in Journal of Molecular Biology
Academic Press Ltd- Elsevier Science Ltd, London., 426(7), 1498-1511.
https://doi.org/10.1016/j.jmb.2013.12.016

Jovanović G, Mehta P, McDonald C, Davidson AC, Uzdavinys P, Ying L, Buck M. The N-Terminal Amphipathic Helices Determine Regulatory and Effector Functions of Phage Shock Protein A (PspA) in Escherichia coli. in Journal of Molecular Biology. 2014;426(7):1498-1511.
doi:10.1016/j.jmb.2013.12.016 .

Jovanović, Goran, Mehta, Parul, McDonald, Christopher, Davidson, Anthony C., Uzdavinys, Povilas, Ying, Liming, Buck, Martin, "The N-Terminal Amphipathic Helices Determine Regulatory and Effector Functions of Phage Shock Protein A (PspA) in Escherichia coli" in Journal of Molecular Biology, 426, no. 7 (2014):1498-1511,
https://doi.org/10.1016/j.jmb.2013.12.016 . .

TY  - JOUR
AU  - Wallrodt, Inke
AU  - Jelsbak, Lotte
AU  - Thomsen, Line E.
AU  - Brix, Lena
AU  - Lemire, Sebastien
AU  - Gautier, Laurent
AU  - Nielsen, Dennis S.
AU  - Jovanović, Goran
AU  - Buck, Martin
AU  - Olsen, John E.
PY  - 2014
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/704
AB  - The phage-shock protein (Psp) system is believed to manage membrane stress in all Enterobacteriaceae and has recently emerged as being important for virulence in several pathogenic species of this phylum. The core of the Psp system consists of the pspA-D operon and the distantly located pspG gene. In Salmonella enterica serovar Typhimurium (S. Typhimurium), it has recently been reported that PspA is essential for systemic infection of mice, but only in NRAMP1(+) mice, signifying that attenuation is related to coping with divalent cation starvation in the intracellular environment. In the present study, we investigated the contribution of individual psp genes to virulence of S. Typhimurium. Interestingly, deletion of the whole pspA-D set of genes caused attenuation in both NRAMP1(+) and NRAMP1(-) mice, indicating that one or more of the psp genes contribute to virulence independently of NRAMP1 expression in the host. Investigations of single gene mutants showed that knock out of pspB reduced virulence in both types of mice, while deletion of pspA only caused attenuation in NRAMP1(+) mice, and deletion of pspD had a minor effect in NRAMP1(-) mice, while deletions of either pspC or pspG did not affect virulence. Experiments addressed at elucidating the role of PspB in virulence revealed that PspB is dispensable for uptake to and intracellular replication in cultured macrophages and resistance to complement-induced killing. Furthermore, the Psp system of S. Typhimurium was dispensable during pIV-induced secretin stress. In conclusion, our results demonstrate that removal of PspB reduces virulence in S. Typhimurium independently of host NRAMP1 expression, demonstrating that PspB has roles in intra-host survival distinct from the reported contributions of PspA.
PB  - Soc General Microbiology, Reading
T2  - Journal of Medical Microbiology
T1  - Removal of the phage-shock protein PspB causes reduction of virulence in Salmonella enterica serovar Typhimurium independently of NRAMP1
EP  - 795
SP  - 788
VL  - 63
DO  - 10.1099/jmm.0.072223-0
ER  - 

@article{
author = "Wallrodt, Inke and Jelsbak, Lotte and Thomsen, Line E. and Brix, Lena and Lemire, Sebastien and Gautier, Laurent and Nielsen, Dennis S. and Jovanović, Goran and Buck, Martin and Olsen, John E.",
year = "2014",
abstract = "The phage-shock protein (Psp) system is believed to manage membrane stress in all Enterobacteriaceae and has recently emerged as being important for virulence in several pathogenic species of this phylum. The core of the Psp system consists of the pspA-D operon and the distantly located pspG gene. In Salmonella enterica serovar Typhimurium (S. Typhimurium), it has recently been reported that PspA is essential for systemic infection of mice, but only in NRAMP1(+) mice, signifying that attenuation is related to coping with divalent cation starvation in the intracellular environment. In the present study, we investigated the contribution of individual psp genes to virulence of S. Typhimurium. Interestingly, deletion of the whole pspA-D set of genes caused attenuation in both NRAMP1(+) and NRAMP1(-) mice, indicating that one or more of the psp genes contribute to virulence independently of NRAMP1 expression in the host. Investigations of single gene mutants showed that knock out of pspB reduced virulence in both types of mice, while deletion of pspA only caused attenuation in NRAMP1(+) mice, and deletion of pspD had a minor effect in NRAMP1(-) mice, while deletions of either pspC or pspG did not affect virulence. Experiments addressed at elucidating the role of PspB in virulence revealed that PspB is dispensable for uptake to and intracellular replication in cultured macrophages and resistance to complement-induced killing. Furthermore, the Psp system of S. Typhimurium was dispensable during pIV-induced secretin stress. In conclusion, our results demonstrate that removal of PspB reduces virulence in S. Typhimurium independently of host NRAMP1 expression, demonstrating that PspB has roles in intra-host survival distinct from the reported contributions of PspA.",
publisher = "Soc General Microbiology, Reading",
journal = "Journal of Medical Microbiology",
title = "Removal of the phage-shock protein PspB causes reduction of virulence in Salmonella enterica serovar Typhimurium independently of NRAMP1",
pages = "795-788",
volume = "63",
doi = "10.1099/jmm.0.072223-0"
}

Wallrodt, I., Jelsbak, L., Thomsen, L. E., Brix, L., Lemire, S., Gautier, L., Nielsen, D. S., Jovanović, G., Buck, M.,& Olsen, J. E.. (2014). Removal of the phage-shock protein PspB causes reduction of virulence in Salmonella enterica serovar Typhimurium independently of NRAMP1. in Journal of Medical Microbiology
Soc General Microbiology, Reading., 63, 788-795.
https://doi.org/10.1099/jmm.0.072223-0

Wallrodt I, Jelsbak L, Thomsen LE, Brix L, Lemire S, Gautier L, Nielsen DS, Jovanović G, Buck M, Olsen JE. Removal of the phage-shock protein PspB causes reduction of virulence in Salmonella enterica serovar Typhimurium independently of NRAMP1. in Journal of Medical Microbiology. 2014;63:788-795.
doi:10.1099/jmm.0.072223-0 .

Wallrodt, Inke, Jelsbak, Lotte, Thomsen, Line E., Brix, Lena, Lemire, Sebastien, Gautier, Laurent, Nielsen, Dennis S., Jovanović, Goran, Buck, Martin, Olsen, John E., "Removal of the phage-shock protein PspB causes reduction of virulence in Salmonella enterica serovar Typhimurium independently of NRAMP1" in Journal of Medical Microbiology, 63 (2014):788-795,
https://doi.org/10.1099/jmm.0.072223-0 . .

TY  - JOUR
AU  - Jovanović, Goran
AU  - Mehta, Parul
AU  - Ying, Liming
AU  - Buck, Martin
PY  - 2014
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/734
AB  - All cell types must maintain the integrity of their membranes. The conserved bacterial membrane-associated protein PspA is a major effector acting upon extracytoplasmic stress and is implicated in protection of the inner membrane of pathogens, formation of biofilms and multi-drug-resistant persister cells. PspA and its homologues in Gram-positive bacteria and archaea protect the cell envelope whilst also supporting thylakoid biogenesis in cyanobacteria and higher plants. In enterobacteria, PspA is a dual function protein negatively regulating the Psp system in the absence of stress and acting as an effector of membrane integrity upon stress. We show that in Escherichia coli the low-order oligomeric PspA regulatory complex associates with cardiolipinrich, curved polar inner membrane regions. There, cardiolipin and the flotillin 1 homologue YqiK support the PspBC sensors in transducing a membrane stress signal to the PspA-PspF inhibitory complex. After stress perception, PspA high-order oligomeric effector complexes initially assemble in polar membrane regions. Subsequently, the discrete spatial distribution and dynamics of PspA effector(s) in lateral membrane regions depend on the actin homologue MreB and the peptidoglycan machinery protein RodZ. The consequences of loss of cytoplasmic membrane anionic lipids, MreB, RodZ and/or YqiK suggest that the mode of action of the PspA effector is closely associated with cell envelope organization.
PB  - Microbiology Soc, London
T2  - Microbiology-Sgm
T1  - Anionic lipids and the cytoskeletal proteins MreB and RodZ define the spatio-temporal distribution and function of membrane stress controller PspA in Escherichia coli
EP  - 2386
SP  - 2374
VL  - 160
DO  - 10.1099/mic.0.078527-0
ER  - 

@article{
author = "Jovanović, Goran and Mehta, Parul and Ying, Liming and Buck, Martin",
year = "2014",
abstract = "All cell types must maintain the integrity of their membranes. The conserved bacterial membrane-associated protein PspA is a major effector acting upon extracytoplasmic stress and is implicated in protection of the inner membrane of pathogens, formation of biofilms and multi-drug-resistant persister cells. PspA and its homologues in Gram-positive bacteria and archaea protect the cell envelope whilst also supporting thylakoid biogenesis in cyanobacteria and higher plants. In enterobacteria, PspA is a dual function protein negatively regulating the Psp system in the absence of stress and acting as an effector of membrane integrity upon stress. We show that in Escherichia coli the low-order oligomeric PspA regulatory complex associates with cardiolipinrich, curved polar inner membrane regions. There, cardiolipin and the flotillin 1 homologue YqiK support the PspBC sensors in transducing a membrane stress signal to the PspA-PspF inhibitory complex. After stress perception, PspA high-order oligomeric effector complexes initially assemble in polar membrane regions. Subsequently, the discrete spatial distribution and dynamics of PspA effector(s) in lateral membrane regions depend on the actin homologue MreB and the peptidoglycan machinery protein RodZ. The consequences of loss of cytoplasmic membrane anionic lipids, MreB, RodZ and/or YqiK suggest that the mode of action of the PspA effector is closely associated with cell envelope organization.",
publisher = "Microbiology Soc, London",
journal = "Microbiology-Sgm",
title = "Anionic lipids and the cytoskeletal proteins MreB and RodZ define the spatio-temporal distribution and function of membrane stress controller PspA in Escherichia coli",
pages = "2386-2374",
volume = "160",
doi = "10.1099/mic.0.078527-0"
}

Jovanović, G., Mehta, P., Ying, L.,& Buck, M.. (2014). Anionic lipids and the cytoskeletal proteins MreB and RodZ define the spatio-temporal distribution and function of membrane stress controller PspA in Escherichia coli. in Microbiology-Sgm
Microbiology Soc, London., 160, 2374-2386.
https://doi.org/10.1099/mic.0.078527-0

Jovanović G, Mehta P, Ying L, Buck M. Anionic lipids and the cytoskeletal proteins MreB and RodZ define the spatio-temporal distribution and function of membrane stress controller PspA in Escherichia coli. in Microbiology-Sgm. 2014;160:2374-2386.
doi:10.1099/mic.0.078527-0 .

Jovanović, Goran, Mehta, Parul, Ying, Liming, Buck, Martin, "Anionic lipids and the cytoskeletal proteins MreB and RodZ define the spatio-temporal distribution and function of membrane stress controller PspA in Escherichia coli" in Microbiology-Sgm, 160 (2014):2374-2386,
https://doi.org/10.1099/mic.0.078527-0 . .

TY  - JOUR
AU  - Mehta, Parul
AU  - Jovanović, Goran
AU  - Lenn, Tchern
AU  - Bruckbauer, Andreas
AU  - Engl, Christoph
AU  - Ying, Liming
AU  - Buck, Martin
PY  - 2013
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/660
AB  - Bacterial enhancer-dependent transcription systems support major adaptive responses and offer a singular paradigm in gene control analogous to complex eukaryotic systems. Here we report new mechanistic insights into the control of one-membrane stress-responsive bacterial enhancer-dependent system. Using millisecond single-molecule fluorescence microscopy of live cells we determine the localizations, two-dimensional diffusion dynamics and stoichiometries of complexes of the bacterial enhancer-binding ATPase PspF during its action at promoters as regulated by inner membrane interacting negative controller PspA. We establish that a stable repressive PspF-PspA complex is located in the nucleoid, transiently communicating with the inner membrane via PspA. The PspF as a hexamer stably binds only one of the two psp promoters at a time, suggesting that psp promoters will fire asynchronously and cooperative interactions of PspF with the basal transcription complex influence dynamics of the PspF hexamer-DNA complex and regulation of the psp promoters.
PB  - Nature Publishing Group, London
T2  - Nature Communications
T1  - Dynamics and stoichiometry of a regulated enhancer-binding protein in live Escherichia coli cells
VL  - 4
DO  - 10.1038/ncomms2997
ER  - 

@article{
author = "Mehta, Parul and Jovanović, Goran and Lenn, Tchern and Bruckbauer, Andreas and Engl, Christoph and Ying, Liming and Buck, Martin",
year = "2013",
abstract = "Bacterial enhancer-dependent transcription systems support major adaptive responses and offer a singular paradigm in gene control analogous to complex eukaryotic systems. Here we report new mechanistic insights into the control of one-membrane stress-responsive bacterial enhancer-dependent system. Using millisecond single-molecule fluorescence microscopy of live cells we determine the localizations, two-dimensional diffusion dynamics and stoichiometries of complexes of the bacterial enhancer-binding ATPase PspF during its action at promoters as regulated by inner membrane interacting negative controller PspA. We establish that a stable repressive PspF-PspA complex is located in the nucleoid, transiently communicating with the inner membrane via PspA. The PspF as a hexamer stably binds only one of the two psp promoters at a time, suggesting that psp promoters will fire asynchronously and cooperative interactions of PspF with the basal transcription complex influence dynamics of the PspF hexamer-DNA complex and regulation of the psp promoters.",
publisher = "Nature Publishing Group, London",
journal = "Nature Communications",
title = "Dynamics and stoichiometry of a regulated enhancer-binding protein in live Escherichia coli cells",
volume = "4",
doi = "10.1038/ncomms2997"
}

Mehta, P., Jovanović, G., Lenn, T., Bruckbauer, A., Engl, C., Ying, L.,& Buck, M.. (2013). Dynamics and stoichiometry of a regulated enhancer-binding protein in live Escherichia coli cells. in Nature Communications
Nature Publishing Group, London., 4.
https://doi.org/10.1038/ncomms2997

Mehta P, Jovanović G, Lenn T, Bruckbauer A, Engl C, Ying L, Buck M. Dynamics and stoichiometry of a regulated enhancer-binding protein in live Escherichia coli cells. in Nature Communications. 2013;4.
doi:10.1038/ncomms2997 .

Mehta, Parul, Jovanović, Goran, Lenn, Tchern, Bruckbauer, Andreas, Engl, Christoph, Ying, Liming, Buck, Martin, "Dynamics and stoichiometry of a regulated enhancer-binding protein in live Escherichia coli cells" in Nature Communications, 4 (2013),
https://doi.org/10.1038/ncomms2997 . .

TY  - JOUR
AU  - Engl, Christoph
AU  - Ter Beek, Alex
AU  - Bekker, Martijn
AU  - de Mattos, Joost Teixeira
AU  - Jovanović, Goran
AU  - Buck, Martin
PY  - 2011
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/530
AB  - Phage shock proteins (Psp) and their homologues are found in species from the three domains of life: Bacteria, Archaea and Eukarya (e.g. higher plants). In enterobacteria, the Psp response helps to maintain the proton motive force (PMF) of the cell when the inner membrane integrity is impaired. The presumed ability of ArcB to sense redox changes in the cellular quinone pool and the strong decrease of psp induction in Delta ubiG or Delta arcAB backgrounds suggest a link between the Psp response and the quinone pool. The authors now provide evidence indicating that the physiological signal for inducing psp by secretin-induced stress is neither the quinone redox state nor a drop in PMF. Neither the loss of the H+-gradient nor the dissipation of the electrical potential alone is sufficient to induce the Psp response. A set of electron transport mutants differing in their redox states due to the lack of a NADH dehydrogenase and a quinol oxidase, but retaining a normal PMF displayed low levels of psp induction inversely related to oxidised ubiquinone levels under microaerobic growth and independent of PMF. In contrast, cells displaying higher secretin induced psp expression showed increased levels of ubiquinone. Taken together, this study suggests that not a single but likely multiple signals are needed to be integrated to induce the Psp response.
PB  - Springer, New York
T2  - Current Microbiology
T1  - Dissipation of Proton Motive Force is not Sufficient to Induce the Phage Shock Protein Response in Escherichia coli
EP  - 1385
IS  - 5
SP  - 1374
VL  - 62
DO  - 10.1007/s00284-011-9869-5
ER  - 

@article{
author = "Engl, Christoph and Ter Beek, Alex and Bekker, Martijn and de Mattos, Joost Teixeira and Jovanović, Goran and Buck, Martin",
year = "2011",
abstract = "Phage shock proteins (Psp) and their homologues are found in species from the three domains of life: Bacteria, Archaea and Eukarya (e.g. higher plants). In enterobacteria, the Psp response helps to maintain the proton motive force (PMF) of the cell when the inner membrane integrity is impaired. The presumed ability of ArcB to sense redox changes in the cellular quinone pool and the strong decrease of psp induction in Delta ubiG or Delta arcAB backgrounds suggest a link between the Psp response and the quinone pool. The authors now provide evidence indicating that the physiological signal for inducing psp by secretin-induced stress is neither the quinone redox state nor a drop in PMF. Neither the loss of the H+-gradient nor the dissipation of the electrical potential alone is sufficient to induce the Psp response. A set of electron transport mutants differing in their redox states due to the lack of a NADH dehydrogenase and a quinol oxidase, but retaining a normal PMF displayed low levels of psp induction inversely related to oxidised ubiquinone levels under microaerobic growth and independent of PMF. In contrast, cells displaying higher secretin induced psp expression showed increased levels of ubiquinone. Taken together, this study suggests that not a single but likely multiple signals are needed to be integrated to induce the Psp response.",
publisher = "Springer, New York",
journal = "Current Microbiology",
title = "Dissipation of Proton Motive Force is not Sufficient to Induce the Phage Shock Protein Response in Escherichia coli",
pages = "1385-1374",
number = "5",
volume = "62",
doi = "10.1007/s00284-011-9869-5"
}

Engl, C., Ter Beek, A., Bekker, M., de Mattos, J. T., Jovanović, G.,& Buck, M.. (2011). Dissipation of Proton Motive Force is not Sufficient to Induce the Phage Shock Protein Response in Escherichia coli. in Current Microbiology
Springer, New York., 62(5), 1374-1385.
https://doi.org/10.1007/s00284-011-9869-5

Engl C, Ter Beek A, Bekker M, de Mattos JT, Jovanović G, Buck M. Dissipation of Proton Motive Force is not Sufficient to Induce the Phage Shock Protein Response in Escherichia coli. in Current Microbiology. 2011;62(5):1374-1385.
doi:10.1007/s00284-011-9869-5 .

Engl, Christoph, Ter Beek, Alex, Bekker, Martijn, de Mattos, Joost Teixeira, Jovanović, Goran, Buck, Martin, "Dissipation of Proton Motive Force is not Sufficient to Induce the Phage Shock Protein Response in Escherichia coli" in Current Microbiology, 62, no. 5 (2011):1374-1385,
https://doi.org/10.1007/s00284-011-9869-5 . .

TY  - JOUR
AU  - Toni, Tina
AU  - Jovanović, Goran
AU  - Huvet, Maxime
AU  - Buck, Martin
AU  - Stumpf, Michael P. H.
PY  - 2011
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/511
AB  - Background: Bacteria have evolved a rich set of mechanisms for sensing and adapting to adverse conditions in their environment. These are crucial for their survival, which requires them to react to extracellular stresses such as heat shock, ethanol treatment or phage infection. Here we focus on studying the phage shock protein (Psp) stress response in Escherichia coli induced by a phage infection or other damage to the bacterial membrane. This system has not yet been theoretically modelled or analysed in silico. Results: We develop a model of the Psp response system, and illustrate how such models can be constructed and analyzed in light of available sparse and qualitative information in order to generate novel biological hypotheses about their dynamical behaviour. We analyze this model using tools from Petri-net theory and study its dynamical range that is consistent with currently available knowledge by conditioning model parameters on the available data in an approximate Bayesian computation (ABC) framework. Within this ABC approach we analyze stochastic and deterministic dynamics. This analysis allows us to identify different types of behaviour and these mechanistic insights can in turn be used to design new, more detailed and time-resolved experiments. Conclusions: We have developed the first mechanistic model of the Psp response in E. coli. This model allows us to predict the possible qualitative stochastic and deterministic dynamic behaviours of key molecular players in the stress response. Our inferential approach can be applied to stress response and signalling systems more generally: in the ABC framework we can condition mathematical models on qualitative data in order to delimit e. g. parameter ranges or the qualitative system dynamics in light of available end-point or qualitative information.
PB  - BMC, London
T2  - BMC Systems Biology
T1  - From qualitative data to quantitative models: analysis of the phage shock protein stress response in Escherichia coli
VL  - 5
DO  - 10.1186/1752-0509-5-69
ER  - 

@article{
author = "Toni, Tina and Jovanović, Goran and Huvet, Maxime and Buck, Martin and Stumpf, Michael P. H.",
year = "2011",
abstract = "Background: Bacteria have evolved a rich set of mechanisms for sensing and adapting to adverse conditions in their environment. These are crucial for their survival, which requires them to react to extracellular stresses such as heat shock, ethanol treatment or phage infection. Here we focus on studying the phage shock protein (Psp) stress response in Escherichia coli induced by a phage infection or other damage to the bacterial membrane. This system has not yet been theoretically modelled or analysed in silico. Results: We develop a model of the Psp response system, and illustrate how such models can be constructed and analyzed in light of available sparse and qualitative information in order to generate novel biological hypotheses about their dynamical behaviour. We analyze this model using tools from Petri-net theory and study its dynamical range that is consistent with currently available knowledge by conditioning model parameters on the available data in an approximate Bayesian computation (ABC) framework. Within this ABC approach we analyze stochastic and deterministic dynamics. This analysis allows us to identify different types of behaviour and these mechanistic insights can in turn be used to design new, more detailed and time-resolved experiments. Conclusions: We have developed the first mechanistic model of the Psp response in E. coli. This model allows us to predict the possible qualitative stochastic and deterministic dynamic behaviours of key molecular players in the stress response. Our inferential approach can be applied to stress response and signalling systems more generally: in the ABC framework we can condition mathematical models on qualitative data in order to delimit e. g. parameter ranges or the qualitative system dynamics in light of available end-point or qualitative information.",
publisher = "BMC, London",
journal = "BMC Systems Biology",
title = "From qualitative data to quantitative models: analysis of the phage shock protein stress response in Escherichia coli",
volume = "5",
doi = "10.1186/1752-0509-5-69"
}

Toni, T., Jovanović, G., Huvet, M., Buck, M.,& Stumpf, M. P. H.. (2011). From qualitative data to quantitative models: analysis of the phage shock protein stress response in Escherichia coli. in BMC Systems Biology
BMC, London., 5.
https://doi.org/10.1186/1752-0509-5-69

Toni T, Jovanović G, Huvet M, Buck M, Stumpf MPH. From qualitative data to quantitative models: analysis of the phage shock protein stress response in Escherichia coli. in BMC Systems Biology. 2011;5.
doi:10.1186/1752-0509-5-69 .

Toni, Tina, Jovanović, Goran, Huvet, Maxime, Buck, Martin, Stumpf, Michael P. H., "From qualitative data to quantitative models: analysis of the phage shock protein stress response in Escherichia coli" in BMC Systems Biology, 5 (2011),
https://doi.org/10.1186/1752-0509-5-69 . .

TY  - JOUR
AU  - Lenn, Tchern
AU  - Gkekas, Christos N.
AU  - Bernard, Laurent
AU  - Engl, Christoph
AU  - Jovanović, Goran
AU  - Buck, Martin
AU  - Ying, Liming
PY  - 2011
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/474
AB  - We report a general method based on wide-field fluorescence imaging of single molecule photobleaching and the Chung-Kennedy algorithm to measure the stoichiometry of functional protein complexes in living bacterial cells.
PB  - Royal Soc Chemistry, Cambridge
T2  - Chemical Communications
T1  - Measuring the stoichiometry of functional PspA complexes in living bacterial cells by single molecule photobleaching
EP  - 402
IS  - 1
SP  - 400
VL  - 47
DO  - 10.1039/c0cc01707h
ER  - 

@article{
author = "Lenn, Tchern and Gkekas, Christos N. and Bernard, Laurent and Engl, Christoph and Jovanović, Goran and Buck, Martin and Ying, Liming",
year = "2011",
abstract = "We report a general method based on wide-field fluorescence imaging of single molecule photobleaching and the Chung-Kennedy algorithm to measure the stoichiometry of functional protein complexes in living bacterial cells.",
publisher = "Royal Soc Chemistry, Cambridge",
journal = "Chemical Communications",
title = "Measuring the stoichiometry of functional PspA complexes in living bacterial cells by single molecule photobleaching",
pages = "402-400",
number = "1",
volume = "47",
doi = "10.1039/c0cc01707h"
}

Lenn, T., Gkekas, C. N., Bernard, L., Engl, C., Jovanović, G., Buck, M.,& Ying, L.. (2011). Measuring the stoichiometry of functional PspA complexes in living bacterial cells by single molecule photobleaching. in Chemical Communications
Royal Soc Chemistry, Cambridge., 47(1), 400-402.
https://doi.org/10.1039/c0cc01707h

Lenn T, Gkekas CN, Bernard L, Engl C, Jovanović G, Buck M, Ying L. Measuring the stoichiometry of functional PspA complexes in living bacterial cells by single molecule photobleaching. in Chemical Communications. 2011;47(1):400-402.
doi:10.1039/c0cc01707h .

Lenn, Tchern, Gkekas, Christos N., Bernard, Laurent, Engl, Christoph, Jovanović, Goran, Buck, Martin, Ying, Liming, "Measuring the stoichiometry of functional PspA complexes in living bacterial cells by single molecule photobleaching" in Chemical Communications, 47, no. 1 (2011):400-402,
https://doi.org/10.1039/c0cc01707h . .

TY  - JOUR
AU  - Jovanović, Goran
AU  - Engl, Christoph
AU  - Mayhew, Antony J.
AU  - Burrows, Patricia C.
AU  - Buck, Martin
PY  - 2010
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/437
AB  - The phage-shock-protein (Psp) response maintains the proton-motive force (pmf) under extracytoplasmic stress conditions that impair the inner membrane (IM) in bacterial cells. In Escherichia coli transcription of the pspABCDE and pspG genes requires activation of sigma(54)-RNA polymerase by the enhancer-binding protein PspF. A regulatory network comprising PspF-A -C-B-ArcB controls psp expression. One key regulatory point is the negative control of PspF imposed by its binding to PspA. It has been proposed that under stress conditions, the IM-bound sensors PspB and PspC receive and transduce the signal(s) to PspA via protein-protein interactions, resulting in the release of the PspA PspF inhibitory complex and the consequent induction of psp. In this work we demonstrate that PspB self-associates and interacts with PspC via putative IM regions. We present evidence suggesting that PspC has two topologies and that conserved residue G48 and the putative leucine zipper motif are determinants required for PspA interaction and signal transduction upon stress. We also establish that PspC directly interacts with the effector PspG, and show that PspG self-associates. These results are discussed in the context of formation and function of the Psp regulatory complex.
PB  - Microbiology Soc, London
T2  - Microbiology-Sgm
T1  - Properties of the phage-shock-protein (Psp) regulatory complex that govern signal transduction and induction of the Psp response in Escherichia coli
EP  - 2932
SP  - 2920
VL  - 156
DO  - 10.1099/mic.0.040055-0
ER  - 

@article{
author = "Jovanović, Goran and Engl, Christoph and Mayhew, Antony J. and Burrows, Patricia C. and Buck, Martin",
year = "2010",
abstract = "The phage-shock-protein (Psp) response maintains the proton-motive force (pmf) under extracytoplasmic stress conditions that impair the inner membrane (IM) in bacterial cells. In Escherichia coli transcription of the pspABCDE and pspG genes requires activation of sigma(54)-RNA polymerase by the enhancer-binding protein PspF. A regulatory network comprising PspF-A -C-B-ArcB controls psp expression. One key regulatory point is the negative control of PspF imposed by its binding to PspA. It has been proposed that under stress conditions, the IM-bound sensors PspB and PspC receive and transduce the signal(s) to PspA via protein-protein interactions, resulting in the release of the PspA PspF inhibitory complex and the consequent induction of psp. In this work we demonstrate that PspB self-associates and interacts with PspC via putative IM regions. We present evidence suggesting that PspC has two topologies and that conserved residue G48 and the putative leucine zipper motif are determinants required for PspA interaction and signal transduction upon stress. We also establish that PspC directly interacts with the effector PspG, and show that PspG self-associates. These results are discussed in the context of formation and function of the Psp regulatory complex.",
publisher = "Microbiology Soc, London",
journal = "Microbiology-Sgm",
title = "Properties of the phage-shock-protein (Psp) regulatory complex that govern signal transduction and induction of the Psp response in Escherichia coli",
pages = "2932-2920",
volume = "156",
doi = "10.1099/mic.0.040055-0"
}

Jovanović, G., Engl, C., Mayhew, A. J., Burrows, P. C.,& Buck, M.. (2010). Properties of the phage-shock-protein (Psp) regulatory complex that govern signal transduction and induction of the Psp response in Escherichia coli. in Microbiology-Sgm
Microbiology Soc, London., 156, 2920-2932.
https://doi.org/10.1099/mic.0.040055-0

Jovanović G, Engl C, Mayhew AJ, Burrows PC, Buck M. Properties of the phage-shock-protein (Psp) regulatory complex that govern signal transduction and induction of the Psp response in Escherichia coli. in Microbiology-Sgm. 2010;156:2920-2932.
doi:10.1099/mic.0.040055-0 .

Jovanović, Goran, Engl, Christoph, Mayhew, Antony J., Burrows, Patricia C., Buck, Martin, "Properties of the phage-shock-protein (Psp) regulatory complex that govern signal transduction and induction of the Psp response in Escherichia coli" in Microbiology-Sgm, 156 (2010):2920-2932,
https://doi.org/10.1099/mic.0.040055-0 . .

TY  - JOUR
AU  - Joly, Nicolas
AU  - Engl, Christoph
AU  - Jovanović, Goran
AU  - Huvet, Maxime
AU  - Toni, Tina
AU  - Sheng, Xia
AU  - Stumpf, Michael P. H.
AU  - Buck, Martin
PY  - 2010
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/454
AB  - The bacterial phage shock protein (Psp) response functions to help cells manage the impacts of agents impairing cell membrane function. The system has relevance to biotechnology and to medicine. Originally discovered in Escherichia coli, Psp proteins and homologues are found in Gram-positive and Gram-negative bacteria, in archaea and in plants. Study of the E. coli and Yersinia enterocolitica Psp systems provides insights into how membrane-associated sensory Psp proteins might perceive membrane stress, signal to the transcription apparatus and use an ATP-hydrolysing transcription activator to produce effector proteins to overcome the stress. Progress in understanding the mechanism of signal transduction by the membrane-bound Psp proteins, regulation of the psp gene-specific transcription activator and the cell biology of the system is presented and discussed. Many features of the action of the Psp system appear to be dominated by states of self-association of the master effector, PspA, and the transcription activator, PspF, alongside a signalling pathway that displays strong conditionality in its requirement.
PB  - Oxford Univ Press, Oxford
T2  - FEMS Microbiology Reviews
T1  - Managing membrane stress: the phage shock protein (Psp) response, from molecular mechanisms to physiology
EP  - 827
IS  - 5
SP  - 797
VL  - 34
DO  - 10.1111/j.1574-6976.2010.00240.x
ER  - 

@article{
author = "Joly, Nicolas and Engl, Christoph and Jovanović, Goran and Huvet, Maxime and Toni, Tina and Sheng, Xia and Stumpf, Michael P. H. and Buck, Martin",
year = "2010",
abstract = "The bacterial phage shock protein (Psp) response functions to help cells manage the impacts of agents impairing cell membrane function. The system has relevance to biotechnology and to medicine. Originally discovered in Escherichia coli, Psp proteins and homologues are found in Gram-positive and Gram-negative bacteria, in archaea and in plants. Study of the E. coli and Yersinia enterocolitica Psp systems provides insights into how membrane-associated sensory Psp proteins might perceive membrane stress, signal to the transcription apparatus and use an ATP-hydrolysing transcription activator to produce effector proteins to overcome the stress. Progress in understanding the mechanism of signal transduction by the membrane-bound Psp proteins, regulation of the psp gene-specific transcription activator and the cell biology of the system is presented and discussed. Many features of the action of the Psp system appear to be dominated by states of self-association of the master effector, PspA, and the transcription activator, PspF, alongside a signalling pathway that displays strong conditionality in its requirement.",
publisher = "Oxford Univ Press, Oxford",
journal = "FEMS Microbiology Reviews",
title = "Managing membrane stress: the phage shock protein (Psp) response, from molecular mechanisms to physiology",
pages = "827-797",
number = "5",
volume = "34",
doi = "10.1111/j.1574-6976.2010.00240.x"
}

Joly, N., Engl, C., Jovanović, G., Huvet, M., Toni, T., Sheng, X., Stumpf, M. P. H.,& Buck, M.. (2010). Managing membrane stress: the phage shock protein (Psp) response, from molecular mechanisms to physiology. in FEMS Microbiology Reviews
Oxford Univ Press, Oxford., 34(5), 797-827.
https://doi.org/10.1111/j.1574-6976.2010.00240.x

Joly N, Engl C, Jovanović G, Huvet M, Toni T, Sheng X, Stumpf MPH, Buck M. Managing membrane stress: the phage shock protein (Psp) response, from molecular mechanisms to physiology. in FEMS Microbiology Reviews. 2010;34(5):797-827.
doi:10.1111/j.1574-6976.2010.00240.x .

Joly, Nicolas, Engl, Christoph, Jovanović, Goran, Huvet, Maxime, Toni, Tina, Sheng, Xia, Stumpf, Michael P. H., Buck, Martin, "Managing membrane stress: the phage shock protein (Psp) response, from molecular mechanisms to physiology" in FEMS Microbiology Reviews, 34, no. 5 (2010):797-827,
https://doi.org/10.1111/j.1574-6976.2010.00240.x . .

TY  - JOUR
AU  - Jovanović, Goran
AU  - Engl, Christoph
AU  - Buck, Martin
PY  - 2009
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/395
AB  - P gt The phage shock protein (Psp) system found in enterobacteria is induced in response to impaired inner membrane integrity (where the Psp response is thought to help maintain the proton motive force of the cell) and is implicated in the virulence of pathogens such as Yersinia and Salmonella. We provided evidence that the two-component ArcAB system was involved in induction of the Psp response in Escherichia coli and now report that role of ArcAB is conditional. ArcAB, predominantly through the action of ArcA regulated genes, but also via a direct ArcB-Psp interaction, is required to propagate the protein IV (pIV)-dependent psp-inducing signal(s) during microaerobiosis, but not during aerobiosis or anaerobiosis. We show that ArcB directly interacts with the PspB, possibly by means of the PspB leucine zipper motif, thereby allowing cross-communication between the two systems. In addition we demonstrate that the pIV-dependent induction of psp expression in anaerobiosis is independent of PspBC, establishing that PspA and PspF can function as a minimal Psp system responsive to inner membrane stress.
PB  - Wiley, Hoboken
T2  - Molecular Microbiology
T1  - Physical, functional and conditional interactions between ArcAB and phage shock proteins upon secretin-induced stress in Escherichia coli
EP  - 28
IS  - 1
SP  - 16
VL  - 74
DO  - 10.1111/j.1365-2958.2009.06809.x
ER  - 

@article{
author = "Jovanović, Goran and Engl, Christoph and Buck, Martin",
year = "2009",
abstract = "P gt The phage shock protein (Psp) system found in enterobacteria is induced in response to impaired inner membrane integrity (where the Psp response is thought to help maintain the proton motive force of the cell) and is implicated in the virulence of pathogens such as Yersinia and Salmonella. We provided evidence that the two-component ArcAB system was involved in induction of the Psp response in Escherichia coli and now report that role of ArcAB is conditional. ArcAB, predominantly through the action of ArcA regulated genes, but also via a direct ArcB-Psp interaction, is required to propagate the protein IV (pIV)-dependent psp-inducing signal(s) during microaerobiosis, but not during aerobiosis or anaerobiosis. We show that ArcB directly interacts with the PspB, possibly by means of the PspB leucine zipper motif, thereby allowing cross-communication between the two systems. In addition we demonstrate that the pIV-dependent induction of psp expression in anaerobiosis is independent of PspBC, establishing that PspA and PspF can function as a minimal Psp system responsive to inner membrane stress.",
publisher = "Wiley, Hoboken",
journal = "Molecular Microbiology",
title = "Physical, functional and conditional interactions between ArcAB and phage shock proteins upon secretin-induced stress in Escherichia coli",
pages = "28-16",
number = "1",
volume = "74",
doi = "10.1111/j.1365-2958.2009.06809.x"
}

Jovanović, G., Engl, C.,& Buck, M.. (2009). Physical, functional and conditional interactions between ArcAB and phage shock proteins upon secretin-induced stress in Escherichia coli. in Molecular Microbiology
Wiley, Hoboken., 74(1), 16-28.
https://doi.org/10.1111/j.1365-2958.2009.06809.x

Jovanović G, Engl C, Buck M. Physical, functional and conditional interactions between ArcAB and phage shock proteins upon secretin-induced stress in Escherichia coli. in Molecular Microbiology. 2009;74(1):16-28.
doi:10.1111/j.1365-2958.2009.06809.x .

Jovanović, Goran, Engl, Christoph, Buck, Martin, "Physical, functional and conditional interactions between ArcAB and phage shock proteins upon secretin-induced stress in Escherichia coli" in Molecular Microbiology, 74, no. 1 (2009):16-28,
https://doi.org/10.1111/j.1365-2958.2009.06809.x . .

TY  - CONF
AU  - Huvet, Maxime
AU  - Toni, Tina
AU  - Tan, Hui
AU  - Jovanović, Goran
AU  - Engl, Christoph
AU  - Buck, Martin
AU  - Stumpf, Michael P. H.
PY  - 2009
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/351
AB  - The evolution of proteins is inseparably linked to their function. Because most biological processes involve a number of different proteins, it may become impossible to study the evolutionary properties of proteins in isolation. In the present article, we show how simple mechanistic models of biological processes can complement conventional comparative analyses of biological traits. We use the specific example of the phage-shock stress response, which has been well characterized in Escherichia coli, to elucidate patterns of gene sharing and sequence conservation across bacterial species.
PB  - Portland Press Ltd, London
C3  - Biochemical Society Transactions
T1  - Model-based evolutionary analysis: the natural history of phage-shock stress response
EP  - 767
SP  - 762
VL  - 37
DO  - 10.1042/BST0370762
ER  - 

@conference{
author = "Huvet, Maxime and Toni, Tina and Tan, Hui and Jovanović, Goran and Engl, Christoph and Buck, Martin and Stumpf, Michael P. H.",
year = "2009",
abstract = "The evolution of proteins is inseparably linked to their function. Because most biological processes involve a number of different proteins, it may become impossible to study the evolutionary properties of proteins in isolation. In the present article, we show how simple mechanistic models of biological processes can complement conventional comparative analyses of biological traits. We use the specific example of the phage-shock stress response, which has been well characterized in Escherichia coli, to elucidate patterns of gene sharing and sequence conservation across bacterial species.",
publisher = "Portland Press Ltd, London",
journal = "Biochemical Society Transactions",
title = "Model-based evolutionary analysis: the natural history of phage-shock stress response",
pages = "767-762",
volume = "37",
doi = "10.1042/BST0370762"
}

Huvet, M., Toni, T., Tan, H., Jovanović, G., Engl, C., Buck, M.,& Stumpf, M. P. H.. (2009). Model-based evolutionary analysis: the natural history of phage-shock stress response. in Biochemical Society Transactions
Portland Press Ltd, London., 37, 762-767.
https://doi.org/10.1042/BST0370762

Huvet M, Toni T, Tan H, Jovanović G, Engl C, Buck M, Stumpf MPH. Model-based evolutionary analysis: the natural history of phage-shock stress response. in Biochemical Society Transactions. 2009;37:762-767.
doi:10.1042/BST0370762 .

Huvet, Maxime, Toni, Tina, Tan, Hui, Jovanović, Goran, Engl, Christoph, Buck, Martin, Stumpf, Michael P. H., "Model-based evolutionary analysis: the natural history of phage-shock stress response" in Biochemical Society Transactions, 37 (2009):762-767,
https://doi.org/10.1042/BST0370762 . .

TY  - JOUR
AU  - Engl, Christoph
AU  - Jovanović, Goran
AU  - Lloyd, Louise J.
AU  - Murray, Heath
AU  - Spitaler, Martin
AU  - Ying, Liming
AU  - Errington, Jeff
AU  - Buck, Martin
PY  - 2009
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/354
AB  - The phage shock protein (Psp) response in Gram-negative bacteria counteracts membrane stress. Transcription of the PspF regulon (pspABCDE and pspG) in Escherichia coli is induced upon stresses that dissipate the proton motive force (pmf). Using GFP fusions we have visualized the subcellular localizations of PspA (a negative regulator and effector of Psp) and PspG (an effector of Psp). It has previously been proposed that PspA evenly coates the inner membrane of the cell. We now demonstrate that instead of uniformly covering the entire cell, PspA (and PspG) is highly organized into what appear to be distinct functional classes (complexes at the cell pole and the lateral cell wall). Real-time observations revealed lateral PspA and PspG complexes are highly mobile, but absent in cells lacking MreB. Without the MreB cytoskeleton, induction of the Psp response is still observed, yet these cells fail to maintain pmf under stress conditions. The two spatial subspecies therefore appear to be dynamically and functionally distinct with the polar clusters being associated with sensory function and the mobile complexes with maintenance of pmf.
PB  - Wiley, Hoboken
T2  - Molecular Microbiology
T1  - In vivo localizations of membrane stress controllers PspA and PspG in Escherichia coli
EP  - 396
IS  - 3
SP  - 382
VL  - 73
DO  - 10.1111/j.1365-2958.2009.06776.x
ER  - 

@article{
author = "Engl, Christoph and Jovanović, Goran and Lloyd, Louise J. and Murray, Heath and Spitaler, Martin and Ying, Liming and Errington, Jeff and Buck, Martin",
year = "2009",
abstract = "The phage shock protein (Psp) response in Gram-negative bacteria counteracts membrane stress. Transcription of the PspF regulon (pspABCDE and pspG) in Escherichia coli is induced upon stresses that dissipate the proton motive force (pmf). Using GFP fusions we have visualized the subcellular localizations of PspA (a negative regulator and effector of Psp) and PspG (an effector of Psp). It has previously been proposed that PspA evenly coates the inner membrane of the cell. We now demonstrate that instead of uniformly covering the entire cell, PspA (and PspG) is highly organized into what appear to be distinct functional classes (complexes at the cell pole and the lateral cell wall). Real-time observations revealed lateral PspA and PspG complexes are highly mobile, but absent in cells lacking MreB. Without the MreB cytoskeleton, induction of the Psp response is still observed, yet these cells fail to maintain pmf under stress conditions. The two spatial subspecies therefore appear to be dynamically and functionally distinct with the polar clusters being associated with sensory function and the mobile complexes with maintenance of pmf.",
publisher = "Wiley, Hoboken",
journal = "Molecular Microbiology",
title = "In vivo localizations of membrane stress controllers PspA and PspG in Escherichia coli",
pages = "396-382",
number = "3",
volume = "73",
doi = "10.1111/j.1365-2958.2009.06776.x"
}

Engl, C., Jovanović, G., Lloyd, L. J., Murray, H., Spitaler, M., Ying, L., Errington, J.,& Buck, M.. (2009). In vivo localizations of membrane stress controllers PspA and PspG in Escherichia coli. in Molecular Microbiology
Wiley, Hoboken., 73(3), 382-396.
https://doi.org/10.1111/j.1365-2958.2009.06776.x

Engl C, Jovanović G, Lloyd LJ, Murray H, Spitaler M, Ying L, Errington J, Buck M. In vivo localizations of membrane stress controllers PspA and PspG in Escherichia coli. in Molecular Microbiology. 2009;73(3):382-396.
doi:10.1111/j.1365-2958.2009.06776.x .

Engl, Christoph, Jovanović, Goran, Lloyd, Louise J., Murray, Heath, Spitaler, Martin, Ying, Liming, Errington, Jeff, Buck, Martin, "In vivo localizations of membrane stress controllers PspA and PspG in Escherichia coli" in Molecular Microbiology, 73, no. 3 (2009):382-396,
https://doi.org/10.1111/j.1365-2958.2009.06776.x . .

TY  - JOUR
AU  - Joly, Nicolas
AU  - Burrows, Patricia C.
AU  - Engl, Christoph
AU  - Jovanović, Goran
AU  - Buck, Martin
PY  - 2009
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/369
AB  - To survive and colonise their various environments, including those used during infection, bacteria have developed a variety of adaptive systems. Amongst these is phage shock protein (Psp) response, which can be induced in Escherichia coli upon filamentous phage infection (specifically phage secretin pIV) and by other membrane-damaging agents. The E. coli Psp system comprises seven proteins, of which PspA is the central component. PspA is a bifunctional protein that is directly involved in (i) the negative regulation of the psp-specific transcriptional activator PspF and (ii) the maintenance of membrane integrity in a mechanism proposed to involve the formation of a 36-mer ring complex. Here we established that the PspA negative regulation of PspF ATPase activity is the result of a cooperative inhibition. We present biochemical evidence showing that an inhibitory PspA-PspF regulatory complex, which has significantly reduced PspF ATPase activity, is composed of around six PspF subunits and six PspA subunits, suggesting that PspA exists in at least two different oligomeric assemblies. We now establish that all four putative helical domains of PspA are critical for the formation of the 36-mer. In contrast, not all four helical domains are required for the formation of the inhibitory PspA-PspF complex. Since a range of initial PspF oligomeric states permit formation of the apparent PspA-PspF dodecameric assembly, we conclude that PspA and PspF demonstrate a strong propensity to self-assemble into a single defined heteromeric regulatory complex.
PB  - Academic Press Ltd- Elsevier Science Ltd, London
T2  - Journal of Molecular Biology
T1  - A Lower-Order Oligomer Form of Phage Shock Protein A (PspA) Stably Associates with the Hexameric AAA(+) Transcription Activator Protein PspF for Negative Regulation
EP  - 775
IS  - 4
SP  - 764
VL  - 394
DO  - 10.1016/j.jmb.2009.09.055
ER  - 

@article{
author = "Joly, Nicolas and Burrows, Patricia C. and Engl, Christoph and Jovanović, Goran and Buck, Martin",
year = "2009",
abstract = "To survive and colonise their various environments, including those used during infection, bacteria have developed a variety of adaptive systems. Amongst these is phage shock protein (Psp) response, which can be induced in Escherichia coli upon filamentous phage infection (specifically phage secretin pIV) and by other membrane-damaging agents. The E. coli Psp system comprises seven proteins, of which PspA is the central component. PspA is a bifunctional protein that is directly involved in (i) the negative regulation of the psp-specific transcriptional activator PspF and (ii) the maintenance of membrane integrity in a mechanism proposed to involve the formation of a 36-mer ring complex. Here we established that the PspA negative regulation of PspF ATPase activity is the result of a cooperative inhibition. We present biochemical evidence showing that an inhibitory PspA-PspF regulatory complex, which has significantly reduced PspF ATPase activity, is composed of around six PspF subunits and six PspA subunits, suggesting that PspA exists in at least two different oligomeric assemblies. We now establish that all four putative helical domains of PspA are critical for the formation of the 36-mer. In contrast, not all four helical domains are required for the formation of the inhibitory PspA-PspF complex. Since a range of initial PspF oligomeric states permit formation of the apparent PspA-PspF dodecameric assembly, we conclude that PspA and PspF demonstrate a strong propensity to self-assemble into a single defined heteromeric regulatory complex.",
publisher = "Academic Press Ltd- Elsevier Science Ltd, London",
journal = "Journal of Molecular Biology",
title = "A Lower-Order Oligomer Form of Phage Shock Protein A (PspA) Stably Associates with the Hexameric AAA(+) Transcription Activator Protein PspF for Negative Regulation",
pages = "775-764",
number = "4",
volume = "394",
doi = "10.1016/j.jmb.2009.09.055"
}

Joly, N., Burrows, P. C., Engl, C., Jovanović, G.,& Buck, M.. (2009). A Lower-Order Oligomer Form of Phage Shock Protein A (PspA) Stably Associates with the Hexameric AAA(+) Transcription Activator Protein PspF for Negative Regulation. in Journal of Molecular Biology
Academic Press Ltd- Elsevier Science Ltd, London., 394(4), 764-775.
https://doi.org/10.1016/j.jmb.2009.09.055

Joly N, Burrows PC, Engl C, Jovanović G, Buck M. A Lower-Order Oligomer Form of Phage Shock Protein A (PspA) Stably Associates with the Hexameric AAA(+) Transcription Activator Protein PspF for Negative Regulation. in Journal of Molecular Biology. 2009;394(4):764-775.
doi:10.1016/j.jmb.2009.09.055 .

Joly, Nicolas, Burrows, Patricia C., Engl, Christoph, Jovanović, Goran, Buck, Martin, "A Lower-Order Oligomer Form of Phage Shock Protein A (PspA) Stably Associates with the Hexameric AAA(+) Transcription Activator Protein PspF for Negative Regulation" in Journal of Molecular Biology, 394, no. 4 (2009):764-775,
https://doi.org/10.1016/j.jmb.2009.09.055 . .

TY  - JOUR
AU  - Jovanović, Goran
AU  - Lloyd, Louise J.
AU  - Stumpf, Michael P. H.
AU  - Mayhew, Antony J.
AU  - Buck, Martin
PY  - 2006
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/239
AB  - The phage shock protein (Psp) F regulon response in Escherichia coli is thought to be induced by impaired inner membrane integrity and an associated decrease in proton motive force (pmf). Mechanisms by which the Psp system detects the stress signal and responds have so far remained undetermined. Here we demonstrate that PspA and PspG directly confront a variety of inducing stimuli by switching the cell to anaerobic respiration and fermentation and by down-regulating motility, thereby subtly adjusting and maintaining energy usage and pmf. Additionally, PspG controls iron usage. We show that the Psp-inducing protein IV secretin stress, in the absence of Psp proteins, decreases the pmf in an ArcB-dependent manner and that ArcB is required for amplifying and transducing the stress signal to the PspF regulon. The requirement of the ArcB signal transduction protein for induction of psp provides clear evidence for a direct link between the physiological redox state of the cell, the electron transport chain, and induction of the Psp response. Under normal growth conditions PspA and PspD control the level of activity of ArcB/ArcA system that senses the redox/metabolic state of the cell, whereas under stress conditions PspA, PspD, and PspG deliver their effector functions at least in part by activating ArcB/ArcA through positive feedback.
PB  - Amer Soc Biochemistry Molecular Biology Inc, Bethesda
T2  - Journal of Biological Chemistry
T1  - Induction and function of the phage shock protein extracytoplasmic stress response in Escherichia coli
EP  - 21161
IS  - 30
SP  - 21147
VL  - 281
DO  - 10.1074/jbc.M602323200
ER  - 

@article{
author = "Jovanović, Goran and Lloyd, Louise J. and Stumpf, Michael P. H. and Mayhew, Antony J. and Buck, Martin",
year = "2006",
abstract = "The phage shock protein (Psp) F regulon response in Escherichia coli is thought to be induced by impaired inner membrane integrity and an associated decrease in proton motive force (pmf). Mechanisms by which the Psp system detects the stress signal and responds have so far remained undetermined. Here we demonstrate that PspA and PspG directly confront a variety of inducing stimuli by switching the cell to anaerobic respiration and fermentation and by down-regulating motility, thereby subtly adjusting and maintaining energy usage and pmf. Additionally, PspG controls iron usage. We show that the Psp-inducing protein IV secretin stress, in the absence of Psp proteins, decreases the pmf in an ArcB-dependent manner and that ArcB is required for amplifying and transducing the stress signal to the PspF regulon. The requirement of the ArcB signal transduction protein for induction of psp provides clear evidence for a direct link between the physiological redox state of the cell, the electron transport chain, and induction of the Psp response. Under normal growth conditions PspA and PspD control the level of activity of ArcB/ArcA system that senses the redox/metabolic state of the cell, whereas under stress conditions PspA, PspD, and PspG deliver their effector functions at least in part by activating ArcB/ArcA through positive feedback.",
publisher = "Amer Soc Biochemistry Molecular Biology Inc, Bethesda",
journal = "Journal of Biological Chemistry",
title = "Induction and function of the phage shock protein extracytoplasmic stress response in Escherichia coli",
pages = "21161-21147",
number = "30",
volume = "281",
doi = "10.1074/jbc.M602323200"
}

Jovanović, G., Lloyd, L. J., Stumpf, M. P. H., Mayhew, A. J.,& Buck, M.. (2006). Induction and function of the phage shock protein extracytoplasmic stress response in Escherichia coli. in Journal of Biological Chemistry
Amer Soc Biochemistry Molecular Biology Inc, Bethesda., 281(30), 21147-21161.
https://doi.org/10.1074/jbc.M602323200

Jovanović G, Lloyd LJ, Stumpf MPH, Mayhew AJ, Buck M. Induction and function of the phage shock protein extracytoplasmic stress response in Escherichia coli. in Journal of Biological Chemistry. 2006;281(30):21147-21161.
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Jovanović, Goran, Lloyd, Louise J., Stumpf, Michael P. H., Mayhew, Antony J., Buck, Martin, "Induction and function of the phage shock protein extracytoplasmic stress response in Escherichia coli" in Journal of Biological Chemistry, 281, no. 30 (2006):21147-21161,
https://doi.org/10.1074/jbc.M602323200 . .