Forkhead Box Protein 3

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     Forkhead Box Protein 3 (FOXP3) is a member of the Forkhead transcription factor family. It is highly expressed in regulatory T (Treg) cells, a subset of CD4+ T cells that play a critical role in suppressing immune responses, especially those mediated by autoreactive T cells.[1] FOXP3 upregulates a number of genes like Cd25 and Ctla4 and represses other genes like IL-2 and Ptpn22.[2] As with many transcription factors, it cooperates with a number of transcription factor partners to regulate gene expression, including NFAT1, which participates in the inducible expression of cytokine genes like IL-2, IL-4, and TNFα in T cells.[3] A number of mutations to FOXP3 are known to result in a severe autoimmune disease known as IPEX (immune dysregulation, polyendocriopthy, enteropathy, X-linked). As FOXP3 is found on the X-chromosome, mutations to FOXP3 typically only display deleterious phenotypic traits in males, resulting in lymphocyte infiltration and wide spread inflammation in inphants.[4] A similar pathology is also found in mice who carry nonsense mutations in the FOXP3 locus. These mutant mice are known as scurfy mice. The targeted elimination of FOXP3+ CD4+ Tregs in adult mice has similar autoimmune dysfunction.[5] Further, ectopic expression of FOXP3 in peripheral CD4+CD25- T cells equips these T cells with the ability to suppress the proliferation and effector functions of autoreactive T cells in vivo.[6]

     The interaction of FOXP3 with NFAT1 and the FOXP3-NFAT1 target sequences found in IL-2 has been investigated extensively. The appears to form a with a and two unique oligonucleotides, each containing distinct FOXP sites.[7]


[7]

Talk about alignment with FOXP2 and fix the morph.


Structure of the Forkhead domain of FOXP3 bound to NFAT and IL2 Promoter Oligonucleotide (3qrf)

Drag the structure with the mouse to rotate

ReferencesReferences

  1. Josefowicz SZ, Rudensky A. Control of regulatory T cell lineage commitment and maintenance. Immunity. 2009 May;30(5):616-25. PMID:19464984 doi:10.1016/j.immuni.2009.04.009
  2. Zheng Y, Josefowicz SZ, Kas A, Chu TT, Gavin MA, Rudensky AY. Genome-wide analysis of Foxp3 target genes in developing and mature regulatory T cells. Nature. 2007 Feb 22;445(7130):936-40. Epub 2007 Jan 21. PMID:17237761 doi:10.1038/nature05563
  3. Rudra D, Egawa T, Chong MM, Treuting P, Littman DR, Rudensky AY. Runx-CBFbeta complexes control expression of the transcription factor Foxp3 in regulatory T cells. Nat Immunol. 2009 Nov;10(11):1170-7. Epub 2009 Sep 20. PMID:19767756 doi:10.1038/ni.1795
  4. Bennett CL, Christie J, Ramsdell F, Brunkow ME, Ferguson PJ, Whitesell L, Kelly TE, Saulsbury FT, Chance PF, Ochs HD. The immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX) is caused by mutations of FOXP3. Nat Genet. 2001 Jan;27(1):20-1. PMID:11137993 doi:10.1038/83713
  5. Williams LM, Rudensky AY. Maintenance of the Foxp3-dependent developmental program in mature regulatory T cells requires continued expression of Foxp3. Nat Immunol. 2007 Mar;8(3):277-84. Epub 2007 Jan 14. PMID:17220892 doi:10.1038/ni1437
  6. Fontenot JD, Gavin MA, Rudensky AY. Foxp3 programs the development and function of CD4+CD25+ regulatory T cells. Nat Immunol. 2003 Apr;4(4):330-6. Epub 2003 Mar 3. PMID:12612578 doi:10.1038/ni904
  7. 7.0 7.1 Bandukwala HS, Wu Y, Feurer M, Chen Y, Barbosa B, Ghosh S, Stroud JC, Benoist C, Mathis D, Rao A, Chen L. Structure of a Domain-Swapped FOXP3 Dimer on DNA and Its Function in Regulatory T Cells. Immunity. 2011 Mar 30. PMID:21458306 doi:10.1016/j.immuni.2011.02.017

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