In molecular biology, the ferric uptake regulator family is a family of bacterial proteins involved in regulating metal ion uptake and in metal homeostasis. The family is named for its founding member, known as the ferric uptake regulator or ferric uptake regulatory protein (Fur). Fur proteins are responsible for controlling the intracellular concentration of iron in many bacteria. Iron is essential for most organisms, but its concentration must be carefully managed over a wide range of environmental conditions; high concentrations can be toxic due to the formation of reactive oxygen species.[1]
| FUR | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 ferric uptake regulator | |||||||||
| Identifiers | |||||||||
| Symbol | FUR | ||||||||
| Pfam | PF01475 | ||||||||
| Pfam clan | CL0123 | ||||||||
| InterPro | IPR002481 | ||||||||
| SCOP2 | 1mzb / SCOPe / SUPFAM | ||||||||
| |||||||||
| Ferric uptake regulatory protein | |||||||
|---|---|---|---|---|---|---|---|
| Identifiers | |||||||
| Organism | |||||||
| Symbol | Fur | ||||||
| PDB | 2FU4 | ||||||
| UniProt | P0A9A9 | ||||||
| |||||||
Function
editMembers of the ferric uptake regulator family are transcription factors that primarily exert their regulatory effects as repressors: when bound to their cognate metal ion, they are capable of binding DNA and preventing expression of the genes they regulate, but under low concentrations of metal, they undergo a conformational change that prevents DNA binding and lifts the repression.[2][3] In the case of the ferric uptake regulator protein itself, its immediate downstream target is a noncoding RNA called RyhB.[2]
In addition to the ferric uptake regulator protein, members of the Fur family are also involved in maintaining homeostasis with respect to other ions:[4]
- Mur, responsive to manganese.[5][6][7][8][9]
- Nur, responsive to nickel.[10]
- PerR, responsive to peroxide; PerR monomers contain two binding sites and occur in zinc/iron and zinc/manganese forms.[11]
- Zur, responsive to zinc; Zur regulates uptake and transport through a regulon involving ZinT and the transporter ZnuABC.[12][13]
- Irr, responsive to iron through the status of heme biosynthesis. Has both activator and repressor function. Prevalent in Rhizobium, Bradyrhizobium and many other alphaproteobacteria.[14]
The iron dependent repressor family is a functionally similar but non-homologous family of proteins involved in iron homeostasis in prokaryotes.[1]
Relationship to virulence
editMetal homeostasis can be a factor in bacterial virulence, an observation with a particularly long history in the case of iron.[15][16][17] In some cases, expression of virulence factors is under the regulatory control of the Fur protein.[1][2]
References
edit- ^ a b c Pohl E, Haller JC, Mijovilovich A, Meyer-Klaucke W, Garman E, Vasil ML (February 2003). "Architecture of a protein central to iron homeostasis: crystal structure and spectroscopic analysis of the ferric uptake regulator". Molecular Microbiology. 47 (4): 903–15. doi:10.1046/j.1365-2958.2003.03337.x. PMID 12581348. S2CID 38938808.
- ^ a b c Porcheron G, Dozois CM (August 2015). "Interplay between iron homeostasis and virulence: Fur and RyhB as major regulators of bacterial pathogenicity". Veterinary Microbiology. 179 (1–2): 2–14. doi:10.1016/j.vetmic.2015.03.024. PMID 25888312.
- ^ Gilston BA, Wang S, Marcus MD, Canalizo-Hernández MA, Swindell EP, Xue Y, Mondragón A, O'Halloran TV (November 2014). "Structural and mechanistic basis of zinc regulation across the E. coli Zur regulon". PLOS Biology. 12 (11): e1001987. doi:10.1371/journal.pbio.1001987. PMC 4219657. PMID 25369000.
- ^ Waldron KJ, Robinson NJ (January 2009). "How do bacterial cells ensure that metalloproteins get the correct metal?". Nature Reviews. Microbiology. 7 (1): 25–35. doi:10.1038/nrmicro2057. PMID 19079350. S2CID 7253420.
- ^ Díaz-Mireles E, Wexler M, Sawers G, Bellini D, Todd JD, Johnston AW (May 2004). "The Fur-like protein Mur of Rhizobium leguminosarum is a Mn(2+)-responsive transcriptional regulator". Microbiology. 150 (Pt 5): 1447–56. doi:10.1099/mic.0.26961-0. PMID 15133106.
- ^ Platero R, Peixoto L, O'Brian MR, Fabiano E (July 2004). "Fur is involved in manganese-dependent regulation of mntA (sitA) expression in Sinorhizobium meliloti". Applied and Environmental Microbiology. 70 (7): 4349–55. Bibcode:2004ApEnM..70.4349P. doi:10.1128/AEM.70.7.4349-4355.2004. PMC 444773. PMID 15240318.
- ^ Chao TC, Becker A, Buhrmester J, Pühler A, Weidner S (June 2004). "The Sinorhizobium meliloti fur gene regulates, with dependence on Mn(II), transcription of the sitABCD operon, encoding a metal-type transporter". Journal of Bacteriology. 186 (11): 3609–20. doi:10.1128/JB.186.11.3609-3620.2004. PMC 415740. PMID 15150249.
- ^ Hohle TH, O'Brian MR (April 2009). "The mntH gene encodes the major Mn(2+) transporter in Bradyrhizobium japonicum and is regulated by manganese via the Fur protein". Molecular Microbiology. 72 (2): 399–409. doi:10.1111/j.1365-2958.2009.06650.x. PMC 2675660. PMID 19298371.
- ^ Menscher EA, Caswell CC, Anderson ES, Roop RM (February 2012). "Mur regulates the gene encoding the manganese transporter MntH in Brucella abortus 2308". Journal of Bacteriology. 194 (3): 561–6. doi:10.1128/JB.05296-11. PMC 3264066. PMID 22101848.
- ^ Ahn BE, Cha J, Lee EJ, Han AR, Thompson CJ, Roe JH (March 2006). "Nur, a nickel-responsive regulator of the Fur family, regulates superoxide dismutases and nickel transport in Streptomyces coelicolor". Molecular Microbiology. 59 (6): 1848–58. doi:10.1111/j.1365-2958.2006.05065.x. PMID 16553888. S2CID 2728024.
- ^ Lee JW, Helmann JD (March 2006). "The PerR transcription factor senses H2O2 by metal-catalysed histidine oxidation". Nature. 440 (7082): 363–7. Bibcode:2006Natur.440..363L. doi:10.1038/nature04537. PMID 16541078. S2CID 4390980.
- ^ Graham AI, Hunt S, Stokes SL, Bramall N, Bunch J, Cox AG, McLeod CW, Poole RK (July 2009). "Severe zinc depletion of Escherichia coli: roles for high affinity zinc binding by ZinT, zinc transport and zinc-independent proteins". The Journal of Biological Chemistry. 284 (27): 18377–89. doi:10.1074/jbc.M109.001503. PMC 2709383. PMID 19377097.
- ^ Blindauer CA (March 2015). "Advances in the molecular understanding of biological zinc transport" (PDF). Chemical Communications. 51 (22): 4544–63. doi:10.1039/c4cc10174j. PMID 25627157.
- ^ O'Brian MR (2015). "Perception and Homeostatic Control of Iron in the Rhizobia and Related Bacteria". Annual Review of Microbiology. 69: 229–45. doi:10.1146/annurev-micro-091014-104432. PMID 26195304.
- ^ Bullen JJ, Rogers HJ, Griffiths E (1978). "Role of Iron in Bacterial Infection". Modern Aspects of Electrochemistry. Current Topics in Microbiology and Immunology. Vol. 80. pp. 1–35. doi:10.1007/978-3-642-66956-9_1. ISBN 978-1-4612-9003-2. PMID 352628.
- ^ Ratledge C, Dover LG (2000). "Iron metabolism in pathogenic bacteria". Annual Review of Microbiology. 54: 881–941. doi:10.1146/annurev.micro.54.1.881. PMID 11018148.
- ^ Litwin CM, Calderwood SB (April 1993). "Role of iron in regulation of virulence genes". Clinical Microbiology Reviews. 6 (2): 137–49. doi:10.1128/cmr.6.2.137. PMC 358274. PMID 8472246.