4i1l
From Proteopedia
Structural and Biological Features of FOXP3 Dimerization Relevant to Regulatory T Cell Function
Structural highlights
Disease[FOXP3_MOUSE] Defects in Foxp3 are the cause of the scurfy phenotype (sf). It results in a lethal disorder of immunoregulation, characterized by infections, diarrhea, anemia, thrombocytopenia, hypogonadism, gastrointestinal bleeding, lymphadenopathy and leukocytosis. Function[FOXP3_MOUSE] Transcriptional regulator which is crucial for the development and inhibitory function of regulatory T-cells (Treg). Plays an essential role in maintaining homeostasis of the immune system by allowing the acquisition of full suppressive function and stability of the Treg lineage, and by directly modulating the expansion and function of conventional T-cells. Can act either as a transcriptional repressor or a transcriptional activator depending on its interactions with other transcription factors, histone acetylases and deacetylases. The suppressive activity of Treg involves the coordinate activation of many genes, including CTLA4 and TNFRSF18 by FOXP3 along with repression of genes encoding cytokines such as interleukin-2 (IL2) and interferon-gamma (IFNG). Inhibits cytokine production and T-cell effector function by repressing the activity of two key transcription factors, RELA and NFATC2 (PubMed:15790681). Mediates transcriptional repression of IL2 via its association with histone acetylase KAT5 and histone deacetylase HDAC7 (By similarity). Can activate the expression of TNFRSF18, IL2RA and CTLA4 and repress the expression of IL2 and IFNG via its association with transcription factor RUNX1 (PubMed:17377532). Inhibits the differentiation of IL17 producing helper T-cells (Th17) by antagonizing RORC function, leading to down-regulation of IL17 expression, favoring Treg development (PubMed:18368049). Inhibits the transcriptional activator activity of RORA (By similarity). Can repress the expression of IL2 and IFNG via its association with transcription factor IKZF4 (PubMed:19696312).[UniProtKB:Q9BZS1][1] [2] [3] [4] Publication Abstract from PubMedFOXP3 is a key transcription factor for regulatory T cell function. We report the crystal structure of the FOXP3 coiled-coil domain, through which a loose or transient dimeric association is formed and modulated, accounting for the activity variations introduced by disease-causing mutations or posttranslational modifications. Structure-guided mutagenesis revealed that FOXP3 coiled-coil-mediated homodimerization is essential for Treg function in vitro and in vivo. In particular, we identified human FOXP3 K250 and K252 as key residues for the conformational change and stability of the FOXP3 dimer, which can be regulated by protein posttranslational modifications such as reversible lysine acetylation. These studies provide structural and mechanistic explanations for certain disease-causing mutations in the coiled-coil domain of FOXP3 that are commonly found in IPEX syndrome. Overall, the regulatory machinery involving homooligomerization, acetylation, and heteroassociation has been dissected, defining atomic insights into the biological and pathological characteristics of the FOXP3 complex. Structural and biological features of FOXP3 dimerization relevant to regulatory T cell function.,Song X, Li B, Xiao Y, Chen C, Wang Q, Liu Y, Berezov A, Xu C, Gao Y, Li Z, Wu SL, Cai Z, Zhang H, Karger BL, Hancock WW, Wells AD, Zhou Z, Greene MI Cell Rep. 2012 Jun 28;1(6):665-75. Epub 2012 Jun 15. PMID:22813742[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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