scholarly journals Regulation of the Erythrobacter litoralis DSM 8509 general stress response by visible light

2019 ◽  
Author(s):  
Aretha Fiebig ◽  
Lydia M. Varesio ◽  
Xiomarie Alejandro Navarreto ◽  
Sean Crosson
Keyword(s):  
Stress Response ◽  
Visible Light ◽  
Genetic Model ◽  
Multiple Stressors ◽  
Histidine Kinases ◽  
Diverse Range ◽  
General Stress Response ◽  
General Stress ◽  
Sensor Kinases ◽  
Erythrobacter Litoralis

SUMMARYExtracytoplasmic function (ECF) sigma factors are a major class of environmentally-responsive transcriptional regulators. In Alphaproteobacteria the ECF sigma factor, σEcfG, activates general stress response (GSR) transcription and protects cells from multiple stressors. A phosphorylation-dependent protein partner switching mechanism, involving HWE/HisKA_2-family histidine kinases, underlies σEcfG activation. The identity of these sensor kinases and the signals that regulate them remain largely uncharacterized. We have developed the aerobic anoxygenic photoheterotrophic (AAP) bacterium, Erythrobacter litoralis DSM 8509, as a comparative genetic model to investigate GSR regulation. Using this system, we sought to define the contribution of visible light and a photosensory HWE kinase, LovK, to GSR transcription. We identified three HWE kinases that collectively regulate GSR: gsrK and lovK are activators, while gsrP is a repressor. GSR transcription is higher in the dark than light, and the opposing activities of gsrK and gsrP are sufficient to achieve light-dependent differential transcription. In the absence of gsrK and gsrP, lovK alone is sufficient to regulate GSR transcription in response to light. This regulation requires a photochemically active LOV domain in LovK. Our studies establish a role for visible light and HWE kinases in light-dependent regulation of GSR transcription in E. litoralis, an AAP species.GRAPHICAL ABSTRACTABBREVIATED SUMMARYGeneral stress response (GSR) systems protect bacteria from a diverse range of physical and chemical stressors. We have developed Erythrobacter litoralis as a new genetic model to study GSR in Alphaproteobacteria and show that three HWE-family histidine kinases collectively regulate GSR transcription via σEcfG. Visible light is a GSR regulatory signal in E. litoralis, and LovK is a blue-light photosensor kinase that functions as a dark activated GSR regulator.

scholarly journals Regulation of the Erythrobacter litoralis DSM 8509 general stress response by visible light

2019 ◽  
Vol 112 (2) ◽  
pp. 442-460 ◽  
Author(s):  
Aretha Fiebig ◽  
Lydia M. Varesio ◽  
Xiomarie Alejandro Navarreto ◽  
Sean Crosson
Keyword(s):  
Stress Response ◽  
Visible Light ◽  
General Stress Response ◽  
General Stress ◽  
Erythrobacter Litoralis

scholarly journals A single-domain response regulator functions as integrating hub to coordinate general stress response and development in alpha-proteobacteria

2018 ◽  
Author(s):  
C. Lori ◽  
A. Kaczmarczyk ◽  
I. de Jong ◽  
U. Jenal
Keyword(s):  
Stress Response ◽  
Histidine Kinase ◽  
Caulobacter Crescentus ◽  
Response Regulator ◽  
Single Domain ◽  
Histidine Kinases ◽  
General Stress Response ◽  
General Stress ◽  
Phosphoryl Groups ◽  
Alpha Proteobacteria

AbstractThe alpha-proteobacterial general stress response is governed by a conserved partner-switching mechanism that is triggered by phosphorylation of the response regulator PhyR. In the model organism Caulobacter crescentus PhyR was proposed to be phosphorylated by the histidine kinase PhyK, but biochemical evidence in support of such a role of PhyK is missing. Here, we identify a single-domain response regulator, MrrA, that is essential for general stress response activation in C. crescentus. We demonstrate that PhyK does not function as a kinase but accepts phosphoryl groups from MrrA and passes them on to PhyR, thereby adopting the role of a histidine phosphotransferase. MrrA is phosphorylated by at least six histidine kinases that likely serve as stress sensors. MrrA also transfers phosphate to LovK, a histidine kinase involved in C. crescentus holdfast production and attachment, that also negatively regulates the general stress response. We show that LovK together with the response regulator LovR acts as a phosphate sink to redirect phosphate flux away from the PhyKR branch. In agreement with the biochemical data, a mrrA mutant is unable to activate the general stress response and shows a hyper-attachment phenotype, which is linked to decreased expression of the major holdfast inhibitory protein HfiA. We propose that MrrA serves as a central phosphorylation hub that coordinates the general stress response with C. crescentus development and other adaptive behaviors. The characteristic bow-tie architecture of this phosphorylation network with MrrA as the central knot may expedite the evolvability and species-specific niche adaptation of this group of bacteria.ImportanceTwo-component systems (TCSs) consisting of a histidine kinase and a cognate response regulator are predominant signal transduction systems in bacteria. To avoid cross-talk, TCS are generally thought to be highly insulated from each other. However, this notion is based largely on studies of the HisKA subfamily of histidine kinases, while little information is available for the HWE and HisKA2 subfamilies. The latter have been implicated in the alpha-proteobacterial general stress response. Here, we show that in the model organism Caulobacter crescentus an atypical FATGUY-type single-domain response regulator (SDRR), MrrA, is highly promiscuous both in accepting and transferring phosphoryl groups from and to a number of up- and downstream kinases, challenging the current view of strictly insulated TCSs. Instead, we propose that FATGUY response regulators have evolved in alpha-proteobacteria to serve as central phosphorylation hubs to broadly sample information and distribute phosphoryl groups between the general stress response pathway and other TCSs, thereby coordinating multiple cellular behaviors. This signaling cascade includes presumable histidine kinases harboring intact catalytic and ATP-binding (CA) domains that, however, do not function as kinases, but instead have adopted a role as histidine phosphotransferases. Our work highlights a complex phosphorylation network in alpha-proteobacteria that coordinates the general stress response with changes in other cellular behaviors and development.

Activation of the General Stress Response ofBacillus subtilisby Visible Light

2015 ◽  
Vol 91 (5) ◽  
pp. 1032-1045 ◽  
Author(s):  
Jeroen B. van der Steen ◽  
Klaas J. Hellingwerf
Keyword(s):  
Stress Response ◽  
Visible Light ◽  
General Stress Response ◽  
General Stress

scholarly journals Mtl1 Is Required to Activate General Stress Response through Tor1 and Ras2 Inhibition under Conditions of Glucose Starvation and Oxidative Stress

2010 ◽  
Vol 285 (25) ◽  
pp. 19521-19531 ◽  
Author(s):  
Mima Ivanova Petkova ◽  
Nuria Pujol-Carrion ◽  
Javier Arroyo ◽  
Jesús García-Cantalejo ◽  
Maria Angeles de la Torre-Ruiz
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Glucose Starvation ◽  
General Stress Response ◽  
General Stress ◽  
And Oxidative Stress

scholarly journals Modeling the functioning of YtvA in the general stress response in Bacillus subtilis

2013 ◽  
Vol 9 (9) ◽  
pp. 2331 ◽  
Author(s):  
Jeroen B. van der Steen ◽  
Yusuke Nakasone ◽  
Johnny Hendriks ◽  
Klaas J. Hellingwerf
Keyword(s):  
Bacillus Subtilis ◽  
Stress Response ◽  
General Stress Response ◽  
General Stress

scholarly journals Development and optimization of an EGFP-based reporter for measuring the general stress response inListeria monocytogenes

Bioengineered ◽  
2012 ◽  
Vol 3 (2) ◽  
pp. 93-103 ◽  
Author(s):  
Marta Utratna ◽  
Eoin Cosgrave ◽  
Claas Baustian ◽  
Rhodri Ceredig ◽  
Conor O’Byrne
Keyword(s):  
Stress Response ◽  
General Stress Response ◽  
General Stress

scholarly journals Complex general stress response regulation in Sphingomonas melonis Fr1 revealed by transcriptional analyses

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Lisa Gottschlich ◽  
Petra Geiser ◽  
Miriam Bortfeld-Miller ◽  
Christopher M. Field ◽  
Julia A. Vorholt
Keyword(s):  
Stress Response ◽  
General Stress Response ◽  
General Stress
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