The Family of Two-Component Systems That Regulate Hydrocarbon Degradation Pathways
Many bacteria have been isolated in the past that are able to live on toxic aromatic compounds as their sole carbon source. These strains are of great biotechnological interest for bioremediation purposes, since aromatic compounds are components of crude oil and are released, e.g., after a forest fire during the combustion of cellulose and lignins. The degradation pathways involved in braking down these compounds are under tight transcriptional control. However, the mechanisms of regulation differ significantly: some degradation routes are regulated by one-component systems (OCS, transcriptional regulators), whereas other pathways are under the control of two-component systems (TCS). This chapter summarizes knowledge available on the TCS-subfamily that is involved in hydrocarbon degradation. The sensor histidine kinases (SHK) of this subfamily differ significantly from a prototypal SHK in its subcellular localization, size, and domain arrangement. We will focus on data available on the TodS/TodT and TmoS/TmoT systems controlling toluene degradation, and the StyS/StyR system regulating a styrene breakdown pathway. Interestingly, the former two systems are controlled by the concerted action of agonists and antagonists, a fact that is of great interest for the development of efficient bioremediation strategies. A phylogenetic sequence analysis indicates that TCSs with a domain arrangement identical to TodS/TodT are predominantly found in strains of the β- and γ-Proteobacteria that sense and degrade aromatic hydrocarbons or that are involved in processes such as the nodulation, where polyaromatic hydrocarbons (PAHs, flavonoids) are sensed by the TodS homolog NodV.
We acknowledge financial support from FEDER funds and Fondo Social Europeo through grants from the Junta de Andalucía (grants P09-RNM-4509 and CVI-7335) and the Spanish Ministry for Economy and Competitiveness (grants BIO2010-16937 and BIO2013-42297).
- Busch A, Lacal J, Silva-Jímenez H et al (2010) Catabolite repression of the TodS/TodT two-component system and effector-dependent transphosphorylation of TodT as the basis for toluene dioxygenase catabolic pathway control. J Bacteriol 192:4246–4250. https://doi.org/10.1128/JB.00379-10CrossRefPubMedCentralPubMedGoogle Scholar
- Galperin MY (2010) Diversity of structure and function of response regulator output domains. Curr Opin Microbiol 13(2):150–9. https://doi.org/10.1016/j.mib.2010.01.005
- Krell T, Lacal J, Busch A et al (2010) Bacterial sensor kinases: diversity in the recognition of environmental signals. Annu Rev Microbiol 64:539–559. https://doi.org/10.1146/annurev.micro.112408.134054CrossRefPubMedGoogle Scholar
- O’Leary ND, Mooney A, O’Mahony M, Dobson AD (2014) Functional characterization of a StyS sensor kinase reveals distinct domains associated with intracellular and extracellular sensing of styrene in P. putida CA-3. Bioengineered 5:114–122. https://doi.org/10.4161/bioe.28354CrossRefPubMedCentralPubMedGoogle Scholar
- del Peso-Santos T, Shingler V, Perera J (2008) The styrene-responsive StyS/StyR regulation system controls expression of an auxiliary phenylacetyl-coenzyme A ligase: implications for rapid metabolic coupling of the styrene upper- and lower-degradative pathways. Mol Microbiol 69:317–330. https://doi.org/10.1111/j.1365-2958.2008.06259.xCrossRefPubMedGoogle Scholar
- Rampioni G, Leoni L, Pietrangeli B, Zennaro E (2008) The interplay of StyR and IHF regulates substrate-dependent induction and carbon catabolite repression of styrene catabolism genes in Pseudomonas fluorescens ST. BMC Microbiol 8:92. https://doi.org/10.1186/1471-2180-8-92CrossRefPubMedCentralPubMedGoogle Scholar
- Salinero KK, Keller K, Feil WS et al (2009) Metabolic analysis of the soil microbe Dechloromonas aromatica str. RCB: indications of a surprisingly complex life-style and cryptic anaerobic pathways for aromatic degradation. BMC Genomics 10:351. https://doi.org/10.1186/1471-2164-10-351CrossRefPubMedCentralPubMedGoogle Scholar
- Silva-Jímenez H, García-Fontana C, Cadirci BH et al (2012a) Study of the TmoS/TmoT two-component system: towards the functional characterization of the family of TodS/TodT like systems. Microb Biotechnol 5:489–500. https://doi.org/10.1111/j.1751-7915.2011.00322.xCrossRefPubMedCentralPubMedGoogle Scholar