Regulator gene glucosyltransferases (Rgg/SHP) systems

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Regulator gene glucosyltransferases (Rgg, also sometimes known as Gad or Mut) are a family of cell signaling proteins in bacteria. [1] [2] Rgg proteins are part of the RRNPP superfamily of transcriptional regulators [3] and are found in multiple Gram-positive Firmicutes bacteria, such as Streptococcus , Lactobacillus , and Listeria species. The Rgg family of proteins are quorum sensing systems that alter transcription levels by binding to DNA when the Rgg is bound to a cognate signaling Short Hydrophobic Peptide (SHP). [4] The SHP acts as a pheromone (or autoinducer) and is generally secreted by peptidase-containing ABC transporters such as PptAB. [5] It is thought that associated peptidases cleave the SHP into its active form upon secretion. This truncated SHP is then internalized by bacterial cells through a conserved oligopeptidase permease family. [6] The internalized, active SHP then associates with Rgg to form a complex that binds to the promoter region of multiple genes and alters transcription. There can be several different Rgg/SHP paralogs present in a single bacterial strain, usually each with their own specific regulon. While it is theorized that each SHP can only bind to its associated Rgg, there is evidence in some species for crosstalk between different SHPs and Rggs. [7]

Contents

Structure

The structure of the Rgg/SHP complex has been determined by X-ray crystallography. [8] Rggs typically exist in the cell as homodimers, and each monomer has two functional domains: an N-terminal DNA binding domain with a helix-turn-helix (HTH) motif, and a C-terminal peptide binding domain, where the SHP is bound. The SHP consists of an N-terminal secretion signal and a hydrophobic C-terminal region. It is proposed that the N-terminal region is required for exit from the cell, whereas the C-terminal region is necessary for Rgg binding. [9]

Function

The primary function of the Rgg/SHP system is to bind to DNA and regulate gene expression. [10] Rgg/SHP systems can function as either transcriptional activators or repressors, depending on the DNA promoter sequence to which they bind. Activity of the Rgg/SHP systems are often highly dependent on the nutritional content of the surrounding environment. [11]

Regulons

Genes activated by Rgg/SHP systems are typically involved in population level behaviors and environmental adaptation. Rggs were first identified as regulators of expression for glucosyltransferases, [1] but since have been linked to a variety of cellular processes such as the oxidative stress response [12] and sugar metabolism. [13] Several studies have also implicated Rgg/SHP systems in the virulence mechanisms of certain disease-causing bacterial species, such as Streptococcus pneumoniae and Streptococcus pyogenes . Depending on the bacterial species, Rgg/SHP systems are known to up-regulate genes involved in antibiotic resistance, colonization (biology), and biofilm formation. [14] [15]

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<i>Streptococcus pneumoniae</i> Species of bacterium

Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, spherical bacteria, alpha-hemolytic member of the genus Streptococcus. They are usually found in pairs (diplococci) and do not form spores and are non motile. As a significant human pathogenic bacterium S. pneumoniae was recognized as a major cause of pneumonia in the late 19th century, and is the subject of many humoral immunity studies.

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<i>Pseudomonas aeruginosa</i> Species of bacterium

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<span class="mw-page-title-main">Lysin</span>

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References

  1. 1 2 Sulavik, M. C.; Tardif, G.; Clewell, D. B. (1992). "Identification of a gene, RGG, which regulates expression of glucosyltransferase and influences the SPP phenotype of Streptococcus gordonii Challis". Journal of Bacteriology. 174 (11): 3577–3586. doi:10.1128/jb.174.11.3577-3586.1992. PMC   206044 . PMID   1534326.
  2. ↑ Qi, Fengxia; Chen, Ping; Caufield, Page W. (1999). "Functional Analyses of the Promoters in the Lantibiotic Mutacin II Biosynthetic Locus in Streptococcus mutans". Applied and Environmental Microbiology. 65 (2): 652–658. Bibcode:1999ApEnM..65..652Q. doi:10.1128/aem.65.2.652-658.1999. PMC   91075 . PMID   9925596.
  3. ↑ Aggarwal, Surya D.; Yesilkaya, Hasan; Dawid, Suzanne; Hiller, N. Luisa (2020). "The pneumococcal social network". PLOS Pathogens. 16 (10): e1008931. doi: 10.1371/journal.ppat.1008931 . PMC   7595303 . PMID   33119698.
  4. ↑ Fleuchot, B.; Gitton, C.; Guillot, A.; Vidic, J.; Nicolas, P.; Besset, C.; Fontaine, L.; Hols, P.; Leblond-Bourget, N.; Monnet, V.; Gardan, R. (2011). "RGG proteins associated with internalized small hydrophobic peptides: A new quorum-sensing mechanism in streptococci". Molecular Microbiology. 80 (4): 1102–1119. doi:10.1111/j.1365-2958.2011.07633.x. PMID   21435032.
  5. ↑ Chang, Jennifer C.; Federle, Michael J. (2016). "PptAB Exports RGG Quorum-Sensing Peptides in Streptococcus". PLOS ONE. 11 (12): e0168461. Bibcode:2016PLoSO..1168461C. doi: 10.1371/journal.pone.0168461 . PMC   5167397 . PMID   27992504.
  6. ↑ Linton, Kenneth J.; Higgins, Christopher F. (2007). "Structure and function of ABC transporters: The ATP switch provides flexible control". Pflügers Archiv - European Journal of Physiology. 453 (5): 555–567. doi:10.1007/s00424-006-0126-x. PMID   16937116.
  7. ↑ Chang, Jennifer C.; Jimenez, Juan Cristobal; Federle, Michael J. (2015). "Induction of a quorum sensing pathway by environmental signals enhances group <SCP>A</SCP> streptococcal resistance to lysozyme". Molecular Microbiology. 97 (6): 1097–1113. doi:10.1111/mmi.13088. PMC   4674269 . PMID   26062094.
  8. ↑ Parashar, Vijay; Aggarwal, Chaitanya; Federle, Michael J.; Neiditch, Matthew B. (2015). "RGG protein structure–function and inhibition by cyclic peptide compounds". Proceedings of the National Academy of Sciences. 112 (16): 5177–5182. Bibcode:2015PNAS..112.5177P. doi: 10.1073/pnas.1500357112 . PMC   4413276 . PMID   25847993.
  9. ↑ Aggarwal, C.; Jimenez, J. C.; Nanavati, D.; Federle, M. J. (2014). "Multiple length peptide-pheromone variants produced by Streptococcus pyogenes directly bind RGG proteins to confer transcriptional regulation". The Journal of Biological Chemistry. 289 (32): 22427–22436. doi: 10.1074/jbc.M114.583989 . PMC   4139249 . PMID   24958729.
  10. ↑ Jimenez, Juan Cristobal; Federle, Michael J. (2014-09-12). "Quorum sensing in group A Streptococcus". Frontiers in Cellular and Infection Microbiology. 4: 127. doi: 10.3389/fcimb.2014.00127 . ISSN   2235-2988. PMC   4162386 . PMID   25309879.
  11. ↑ Xie, Zhoujie; Meng, Kai; Yang, Xiaoli; Liu, Jie; Yu, Jie; Zheng, Chunyang; Cao, Wei; Liu, Hao (2019-04-18). "Identification of a Quorum Sensing System Regulating Capsule Polysaccharide Production and Biofilm Formation in Streptococcus zooepidemicus". Frontiers in Cellular and Infection Microbiology. 9: 121. doi: 10.3389/fcimb.2019.00121 . ISSN   2235-2988. PMC   6482233 . PMID   31058104.
  12. ↑ Bortoni, Magda E.; Terra, Vanessa S.; Hinds, Jason; Andrew, Peter W.; Yesilkaya, Hasan (2009). "The pneumococcal response to oxidative stress includes a role for RGG". Microbiology. 155 (12): 4123–4134. doi: 10.1099/mic.0.028282-0 . PMC   2885668 . PMID   19762446.
  13. ↑ Shlla, Bushra; Gazioglu, Ozcan; Shafeeq, Sulman; Manzoor, Irfan; Kuipers, Oscar P.; Ulijasz, Andrew; Hiller, N. Luisa; Andrew, Peter W.; Yesilkaya, Hasan (2021). "The Rgg1518 transcriptional regulator is a necessary facet of sugar metabolism and virulence in Streptococcus pneumoniae". Molecular Microbiology. 116 (3): 996–1008. doi:10.1111/mmi.14788. PMC   8460608 . PMID   34328238.
  14. ↑ Zhi, Xiangyun; Abdullah, Iman Tajer; Gazioglu, Ozcan; Manzoor, Irfan; Shafeeq, Sulman; Kuipers, Oscar P.; Hiller, N. Luisa; Andrew, Peter W.; Yesilkaya, Hasan (2018). "RGG-SHP regulators are important for pneumococcal colonization and invasion through their effect on mannose utilization and capsule synthesis". Scientific Reports. 8 (1): 6369. Bibcode:2018NatSR...8.6369Z. doi:10.1038/s41598-018-24910-1. PMC   5913232 . PMID   29686372.
  15. ↑ Cuevas, R. A.; Eutsey, R.; Kadam, A.; West-Roberts, J. A.; Woolford, C. A.; Mitchell, A. P.; Mason, K. M.; Hiller, N. L. (2017). "A novel streptococcal cell-cell communication peptide promotes pneumococcal virulence and biofilm formation". Molecular Microbiology. 105 (4): 554–571. doi:10.1111/mmi.13721. PMC   5550342 . PMID   28557053.
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