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RflM mediates target specificity of the RcsCDB phosphorelay system for transcriptional repression of flagellar synthesis in Salmonella enterica.
Mol Microbiol. 2016 09; 101(5):841-55.MM

Abstract

The bacterial flagellum enables directed movement of Salmonella enterica towards favorable conditions in liquid environments. Regulation of flagellar synthesis is tightly controlled by various environmental signals at transcriptional and post-transcriptional levels. The flagellar master regulator FlhD4 C2 resides on top of the flagellar transcriptional hierarchy and is under autogenous control by FlhD4 C2 -dependent activation of the repressor rflM. The inhibitory activity of RflM depends on the presence of RcsB, the response regulator of the RcsCDB phosphorelay system. In this study, we elucidated the molecular mechanism of RflM-dependent repression of flhDC. We show that RcsB and RflM form a heterodimer that coordinately represses flhDC transcription independent of RcsB phosphorylation. RcsB-RflM complex binds to a RcsB box downstream the P1 transcriptional start site of the flhDC promoter with increased affinity compared to RcsB in the absence of RflM. We propose that RflM stabilizes binding of unphosphorylated RcsB to the flhDC promoter in absence of environmental cues. Thus, RflM is a novel auxiliary regulatory protein that mediates target specificity of RcsB for flhDC repression. The cooperative action of the RcsB-RflM repressor complex allows Salmonella to fine-tune initiation of flagellar gene expression and adds another level to the complex regulation of flagellar synthesis.

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Authors+Show Affiliations

Kühne C
Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany.
Singer HM
Microbiologie, Département de Médecine, Université de Fribourg, 1700, Fribourg, Switzerland. Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany.
Grabisch E
Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany.
Codutti L
Centre of Biomolecular Drug Research (BMWZ), Leibniz University Hannover, 30167, Hannover, Germany.
Carlomagno T
Centre of Biomolecular Drug Research (BMWZ), Leibniz University Hannover, 30167, Hannover, Germany. Group of Structural Chemistry, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany.
Scrima A
Junior Research Group Structural Biology of Autophagy, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany.
Erhardt M
Junior Research Group Infection Biology of Salmonella, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany.

MeSH

Bacterial ProteinsFlagellaOperonPhosphorylationPromoter Regions, GeneticProtein Interaction Domains and MotifsSalmonella entericaSalmonella typhimuriumTranscription FactorsTranscription, Genetic

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

27206164

Citation

Kühne, Caroline, et al. "RflM Mediates Target Specificity of the RcsCDB Phosphorelay System for Transcriptional Repression of Flagellar Synthesis in Salmonella Enterica." Molecular Microbiology, vol. 101, no. 5, 2016, pp. 841-55.
Kühne C, Singer HM, Grabisch E, et al. RflM mediates target specificity of the RcsCDB phosphorelay system for transcriptional repression of flagellar synthesis in Salmonella enterica. Mol Microbiol. 2016;101(5):841-55.
Kühne, C., Singer, H. M., Grabisch, E., Codutti, L., Carlomagno, T., Scrima, A., & Erhardt, M. (2016). RflM mediates target specificity of the RcsCDB phosphorelay system for transcriptional repression of flagellar synthesis in Salmonella enterica. Molecular Microbiology, 101(5), 841-55. https://doi.org/10.1111/mmi.13427
Kühne C, et al. RflM Mediates Target Specificity of the RcsCDB Phosphorelay System for Transcriptional Repression of Flagellar Synthesis in Salmonella Enterica. Mol Microbiol. 2016;101(5):841-55. PubMed PMID: 27206164.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - RflM mediates target specificity of the RcsCDB phosphorelay system for transcriptional repression of flagellar synthesis in Salmonella enterica. AU - Kühne,Caroline, AU - Singer,Hanna M, AU - Grabisch,Eva, AU - Codutti,Luca, AU - Carlomagno,Teresa, AU - Scrima,Andrea, AU - Erhardt,Marc, Y1 - 2016/06/27/ PY - 2016/05/18/accepted PY - 2016/5/21/entrez PY - 2016/5/21/pubmed PY - 2017/7/15/medline SP - 841 EP - 55 JF - Molecular microbiology JO - Mol Microbiol VL - 101 IS - 5 N2 - The bacterial flagellum enables directed movement of Salmonella enterica towards favorable conditions in liquid environments. Regulation of flagellar synthesis is tightly controlled by various environmental signals at transcriptional and post-transcriptional levels. The flagellar master regulator FlhD4 C2 resides on top of the flagellar transcriptional hierarchy and is under autogenous control by FlhD4 C2 -dependent activation of the repressor rflM. The inhibitory activity of RflM depends on the presence of RcsB, the response regulator of the RcsCDB phosphorelay system. In this study, we elucidated the molecular mechanism of RflM-dependent repression of flhDC. We show that RcsB and RflM form a heterodimer that coordinately represses flhDC transcription independent of RcsB phosphorylation. RcsB-RflM complex binds to a RcsB box downstream the P1 transcriptional start site of the flhDC promoter with increased affinity compared to RcsB in the absence of RflM. We propose that RflM stabilizes binding of unphosphorylated RcsB to the flhDC promoter in absence of environmental cues. Thus, RflM is a novel auxiliary regulatory protein that mediates target specificity of RcsB for flhDC repression. The cooperative action of the RcsB-RflM repressor complex allows Salmonella to fine-tune initiation of flagellar gene expression and adds another level to the complex regulation of flagellar synthesis. SN - 1365-2958 UR - https://www.unboundmedicine.com/medline/citation/27206164/RflM_mediates_target_specificity_of_the_RcsCDB_phosphorelay_system_for_transcriptional_repression_of_flagellar_synthesis_in_Salmonella_enterica_ DB - PRIME DP - Unbound Medicine ER -