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Interferon-gamma




Interferon, gamma
Interferon gamma, line representation
Available structures: 1eku, 1fg9, 1fyh, 1hig
Identifiers
Symbol(s) IFNG; IFG; IFI
External IDs OMIM: 147570 MGI: 107656 Homologene: 55526
RNA expression pattern

More reference expression data

Orthologs
Human Mouse
Entrez 3458 15978
Ensembl ENSG00000111537 ENSMUSG00000055170
Uniprot P01579 Q6TDH0
Refseq NM_000619 (mRNA)
NP_000610 (protein)
NM_008337 (mRNA)
NP_032363 (protein)
Location Chr 12: 66.83 - 66.84 Mb Chr 10: 117.84 - 117.85 Mb
Pubmed search [1] [2]


Interferon-gamma (IFN-γ) is a dimerized soluble cytokine that is the only member of the type II class of interferons.[1] This interferon was originally called macrophage-activating factor.

Additional recommended knowledge

Contents

Structure of IFN-γ

The IFN-γ monomer consists of a core of six α-helices and an extended unfolded sequence in the C-terminal region.[2][3] This is shown in the structural models below. The α-helices in the core of the structure are numbered 1 to 6.

The biologically active dimer is formed by anti-parallel inter-locking of the two monomers as shown below. In the cartoon model, one monomer is shown in red, the other in blue.

The structural models shown above (see protein data bank code 1FG9) are all shortened at their C-termini by 17 amino acids. Full length IFN-γ is 143 amino acids in length, the models are 126 amino acids in length. Affinity for the glycosaminoglycan heparan sulphate resides solely within the deleted sequence of 17 amino acids.[4]

Biological activity

In contrast to interferon-α and interferon-β which can be expressed by all cells, IFN-γ is secreted by T lymphocytes and NK cells only. Also known as immune interferon, IFN-γ is the only Type II interferon. It is serologically distinct from Type I interferons and it is acid-labile, while the type I variants are acid-stable.

IFN-γ has antiviral, immunoregulatory, and anti-tumour properties.[5] It alters transcription in up to 30 genes producing a variety of physiological and cellular responses. Activation by IFN-γ is achieved by its interaction with a heterodimeric receptor consisting of IFNGR1 & IFNGR2 (interferon gamma receptors). IFN-γ binding to the receptor activates the JAK-STAT pathway. In addition, IFN-γ activates APCs and promotes Th1 differentiation by upregulating the transcription factor T-bet.

IFN-γ is the hallmark cytokine of Th1 cells (Th2 cells produce IL-4). NK cells and CD8+ cytotoxic T cells also produce IFN-γ. IFN-γ suppresses osteoclast formation by rapidly degrading the RANK adaptor protein TRAF6 in the RANK-RANKL signaling pathway, which otherwise stimulates the production of NFκB.

Therapeutic uses

Interferon-gamma
Systematic (IUPAC) name
Human interferon gamma-1b
Identifiers
CAS number 82115-62-6
98059-61-1
ATC code L03AB03
PubChem  ?
DrugBank BTD00017
Chemical data
Formula C761H1206N214O225S6 
Mol. mass 17145.6 g/mol
Pharmacokinetic data
Bioavailability  ?
Metabolism  ?
Half life  ?
Excretion  ?
Therapeutic considerations
Pregnancy cat.

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Legal status
Routes  ?

Interferons are used to treat infectious diseases and cancer.

Scientists at the University of California at Berkeley have recently discovered that Diindolylmethane (DIM), a naturally occurring compound found in Brassica vegetables, upon oral consumption, is a direct and potent activator of Interferon-Gamma production and sensitivity within the body leading the way for the study of this compound as an anti-viral, anti-bacterial and anti-cancer therapeutic. As this is a dietary compound found in edible vegetables, this has caused a lot of excitement in the immunology field. This compound has also been shown to synergize with Interferon-Gamma in the expression and potentiation of the MHC-I Complex, leading to its study as a possible adjuvant to Interferon-gamma therapeutic models.

References

  1. ^ Gray, P. W. and Goeddel, D. V. (1982). "Structure of the human immune interferon gene". Nature 298: 859-863.
  2. ^ Ealick, S. E., Cook, W. J. et al. (1991). "Three-dimensional structure of recombinant human interferon-gamma". Science 252: 698-702.
  3. ^ Thiel, D. J. et al. (2000). "Observation of an unexpected third receptor molecule in the crystal structure of human interferon-γ receptor complex". Structure 8 (9): 927-936.
  4. ^ Vanhaverbeke, C. Simorre, J-P. et al. (2004). "NMR characterization of the interaction between the C-terminal domain of interferon-γ and heparin-derived oligosaccharides" 384: 93-99.
  5. ^ Schroder et al. (2004). "Interferon-γ an overview of signals, mechanisms and functions". Journal of Leukocyte Biology 75: 163-189.

Further reading

  • Hall, Steven S. (1997) A Commotion in the Blood. New York, New York: Henry Holt and Company. ISBN 0-8050-5841-9
  • Information on Interferon and how it relates to hepatitis c
  • Ikeda H, Old LJ, Schreiber RD (2002). "The roles of IFN gamma in protection against tumor development and cancer immunoediting.". Cytokine Growth Factor Rev. 13 (2): 95-109. PMID 11900986.
  • Chesler DA, Reiss CS (2003). "The role of IFN-gamma in immune responses to viral infections of the central nervous system.". Cytokine Growth Factor Rev. 13 (6): 441-54. PMID 12401479.
  • Dessein A, Kouriba B, Eboumbou C, et al. (2005). "Interleukin-13 in the skin and interferon-gamma in the liver are key players in immune protection in human schistosomiasis.". Immunol. Rev. 201: 180-90. doi:10.1111/j.0105-2896.2004.00195.x. PMID 15361241.
  • Joseph AM, Kumar M, Mitra D (2005). "Nef: "necessary and enforcing factor" in HIV infection.". Curr. HIV Res. 3 (1): 87-94. PMID 15638726.
  • Copeland KF (2006). "Modulation of HIV-1 transcription by cytokines and chemokines.". Mini reviews in medicinal chemistry 5 (12): 1093-101. PMID 16375755.
  • Chiba H, Kojima T, Osanai M, Sawada N (2006). "The significance of interferon-gamma-triggered internalization of tight-junction proteins in inflammatory bowel disease.". Sci. STKE 2006 (316): pe1. doi:10.1126/stke.3162006pe1. PMID 16391178.
  • Tellides G, Pober JS (2007). "Interferon-gamma axis in graft arteriosclerosis.". Circ. Res. 100 (5): 622-32. doi:10.1161/01.RES.0000258861.72279.29. PMID 17363708.
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Interferon-gamma". A list of authors is available in Wikipedia.
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