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Pathway Description
Quorum sensing - Autoinducer-2 Biofilm Regulation
Escherichia coli (strain K12)
Category:
Metabolite Pathway
Sub-Category:
Signaling
Created: 2025-03-19
Last Updated: 2025-05-08
In Escherichia coli, Autoinducer-2 (AI-2) plays a pivotal role in biofilm formation by coordinating the expression of genes involved in extracellular matrix production and cell adhesion. AI-2, particularly in the form of (2R,4S)-2-methyl-2,3,3,4-tetrahydroxytetrahydrofuran, functions as a quorum sensing molecule that allows bacteria to sense population density and regulate biofilm-related behaviors. At high concentrations, (2R,4S)-2-methyl-2,3,3,4-tetrahydroxytetrahydrofuran is spontaneously converted to (4S)-4,5-dihydroxy-2,3-pentanedione (DPD), which is then phosphorylated by L-xylulose/3-keto-L-gulonate kinase to form Phospho-AI-2. Phospho-AI-2 inhibits the transcriptional regulator LsrR, relieving its repression of the lsr operon. This enables the transcription of genes encoding the Autoinducer 2 import ATP-binding protein LsrA, Autoinducer 2 import system permease proteins LsrC and LsrD, and the Autoinducer 2-binding protein LsrB, which collectively facilitate the uptake of more (2R,4S)-2-methyl-2,3,3,4-tetrahydroxytetrahydrofuran into the cell. Once inside, LsrG and LsrF convert Phospho-AI-2 into 3-hydroxy-2,4-pentanedione 5-phosphate (3H2P5P), which enters the pentose phosphate pathway (PPP) for further metabolism. Simultaneously, under conditions of low glucose concentration, the cAMP-CRP complex is activated, which in turn activates the csg operon. The csg operon produces CsgD, CsgE, CsgF, and CsgG, with CsgD acting as a master regulator that activates the csgBAC operon (responsible for curli fiber production) and the yhjr-bcsqabzc operon (responsible for cellulose biosynthesis). Curli fibers and cellulose are critical components of the biofilm extracellular matrix, providing structural integrity and facilitating cell-surface and cell-cell adhesion. Thus, through the integration of AI-2 signaling, metabolic regulation, and transcriptional control, E. coli coordinates the production of curli fibers and cellulose, ultimately leading to the formation of robust biofilms.
References
Quorum sensing - Autoinducer-2 Biofilm Regulation References
Brombacher E, Baratto A, Dorel C, Landini P: Gene expression regulation by the Curli activator CsgD protein: modulation of cellulose biosynthesis and control of negative determinants for microbial adhesion. J Bacteriol. 2006 Mar;188(6):2027-37. doi: 10.1128/JB.188.6.2027-2037.2006.
Pubmed: 16513732
Le Quere B, Ghigo JM: BcsQ is an essential component of the Escherichia coli cellulose biosynthesis apparatus that localizes at the bacterial cell pole. Mol Microbiol. 2009 May;72(3):724-40. doi: 10.1111/j.1365-2958.2009.06678.x.
Pubmed: 19400787
Serra DO, Richter AM, Hengge R: Cellulose as an architectural element in spatially structured Escherichia coli biofilms. J Bacteriol. 2013 Dec;195(24):5540-54. doi: 10.1128/JB.00946-13. Epub 2013 Oct 4.
Pubmed: 24097954
Ballen V, Cepas V, Ratia C, Gabasa Y, Soto SM: Clinical Escherichia coli: From Biofilm Formation to New Antibiofilm Strategies. Microorganisms. 2022 May 26;10(6):1103. doi: 10.3390/microorganisms10061103.
Pubmed: 35744621
Cossart P, Gicquel-Sanzey B: Cloning and sequence of the crp gene of Escherichia coli K 12. Nucleic Acids Res. 1982 Feb 25;10(4):1363-78. doi: 10.1093/nar/10.4.1363.
Pubmed: 6280141
Aiba H, Fujimoto S, Ozaki N: Molecular cloning and nucleotide sequencing of the gene for E. coli cAMP receptor protein. Nucleic Acids Res. 1982 Feb 25;10(4):1345-61. doi: 10.1093/nar/10.4.1345.
Pubmed: 6280140
Blattner FR, Plunkett G 3rd, Bloch CA, Perna NT, Burland V, Riley M, Collado-Vides J, Glasner JD, Rode CK, Mayhew GF, Gregor J, Davis NW, Kirkpatrick HA, Goeden MA, Rose DJ, Mau B, Shao Y: The complete genome sequence of Escherichia coli K-12. Science. 1997 Sep 5;277(5331):1453-62. doi: 10.1126/science.277.5331.1453.
Pubmed: 9278503
Burton Z, Burgess RR, Lin J, Moore D, Holder S, Gross CA: The nucleotide sequence of the cloned rpoD gene for the RNA polymerase sigma subunit from E coli K12. Nucleic Acids Res. 1981 Jun 25;9(12):2889-903. doi: 10.1093/nar/9.12.2889.
Pubmed: 6269063
Hayashi K, Morooka N, Yamamoto Y, Fujita K, Isono K, Choi S, Ohtsubo E, Baba T, Wanner BL, Mori H, Horiuchi T: Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110. Mol Syst Biol. 2006;2:2006.0007. doi: 10.1038/msb4100049. Epub 2006 Feb 21.
Pubmed: 16738553
This pathway was propagated using PathWhiz -
Pon, A. et al. Pathways with PathWhiz (2015) Nucleic Acids Res. 43(Web Server issue): W552–W559.
Propagated from SMP0000856
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