5ji0

Structural highlights

Disease

[NCOA1_HUMAN] Note=A chromosomal aberration involving NCOA1 is a cause of rhabdomyosarcoma. Translocation t(2;2)(q35;p23) with PAX3 generates the NCOA1-PAX3 oncogene consisting of the N-terminus part of PAX3 and the C-terminus part of NCOA1. The fusion protein acts as a transcriptional activator. Rhabdomyosarcoma is the most common soft tissue carcinoma in childhood, representing 5-8% of all malignancies in children. [PPARG_HUMAN] Note=Defects in PPARG can lead to type 2 insulin-resistant diabetes and hyptertension. PPARG mutations may be associated with colon cancer. Defects in PPARG may be associated with susceptibility to obesity (OBESITY) [MIM:601665]. It is a condition characterized by an increase of body weight beyond the limitation of skeletal and physical requirements, as the result of excessive accumulation of body fat.^[1] Defects in PPARG are the cause of familial partial lipodystrophy type 3 (FPLD3) [MIM:604367]. Familial partial lipodystrophies (FPLD) are a heterogeneous group of genetic disorders characterized by marked loss of subcutaneous (sc) fat from the extremities. Affected individuals show an increased preponderance of insulin resistance, diabetes mellitus and dyslipidemia.^{[2] [3]} Genetic variations in PPARG can be associated with susceptibility to glioma type 1 (GLM1) [MIM:137800]. Gliomas are central nervous system neoplasms derived from glial cells and comprise astrocytomas, glioblastoma multiforme, oligodendrogliomas, and ependymomas. Note=Polymorphic PPARG alleles have been found to be significantly over-represented among a cohort of American patients with sporadic glioblastoma multiforme suggesting a possible contribution to disease susceptibility.

Function

[RXRA_HUMAN] Receptor for retinoic acid. Retinoic acid receptors bind as heterodimers to their target response elements in response to their ligands, all-trans or 9-cis retinoic acid, and regulate gene expression in various biological processes. The RAR/RXR heterodimers bind to the retinoic acid response elements (RARE) composed of tandem 5'-AGGTCA-3' sites known as DR1-DR5. The high affinity ligand for RXRs is 9-cis retinoic acid. RXRA serves as a common heterodimeric partner for a number of nuclear receptors. The RXR/RAR heterodimers bind to the retinoic acid response elements (RARE) composed of tandem 5'-AGGTCA-3' sites known as DR1-DR5. In the absence of ligand, the RXR-RAR heterodimers associate with a multiprotein complex containing transcription corepressors that induce histone acetylation, chromatin condensation and transcriptional suppression. On ligand binding, the corepressors dissociate from the receptors and associate with the coactivators leading to transcriptional activation. The RXRA/PPARA heterodimer is required for PPARA transcriptional activity on fatty acid oxidation genes such as ACOX1 and the P450 system genes.^{[4] [5] [6] [7]} [NCOA1_HUMAN] Nuclear receptor coactivator that directly binds nuclear receptors and stimulates the transcriptional activities in a hormone-dependent fashion. Involved in the coactivation of different nuclear receptors, such as for steroids (PGR, GR and ER), retinoids (RXRs), thyroid hormone (TRs) and prostanoids (PPARs). Also involved in coactivation mediated by STAT3, STAT5A, STAT5B and STAT6 transcription factors. Displays histone acetyltransferase activity toward H3 and H4; the relevance of such activity remains however unclear. Plays a central role in creating multisubunit coactivator complexes that act via remodeling of chromatin, and possibly acts by participating in both chromatin remodeling and recruitment of general transcription factors. Required with NCOA2 to control energy balance between white and brown adipose tissues. Required for mediating steroid hormone response. Isoform 2 has a higher thyroid hormone-dependent transactivation activity than isoform 1 and isoform 3.^{[8] [9] [10] [11] [12] [13] [14]} [PPARG_HUMAN] Receptor that binds peroxisome proliferators such as hypolipidemic drugs and fatty acids. Once activated by a ligand, the receptor binds to a promoter element in the gene for acyl-CoA oxidase and activates its transcription. It therefore controls the peroxisomal beta-oxidation pathway of fatty acids. Key regulator of adipocyte differentiation and glucose homeostasis. Acts as a critical regulator of gut homeostasis by suppressing NF-kappa-B-mediated proinflammatory responses.^{[15] [16] [17]}

References

1. ↑ Ristow M, Muller-Wieland D, Pfeiffer A, Krone W, Kahn CR. Obesity associated with a mutation in a genetic regulator of adipocyte differentiation. N Engl J Med. 1998 Oct 1;339(14):953-9. PMID:9753710 doi:10.1056/NEJM199810013391403
2. ↑ Hegele RA, Cao H, Frankowski C, Mathews ST, Leff T. PPARG F388L, a transactivation-deficient mutant, in familial partial lipodystrophy. Diabetes. 2002 Dec;51(12):3586-90. PMID:12453919
3. ↑ Agarwal AK, Garg A. A novel heterozygous mutation in peroxisome proliferator-activated receptor-gamma gene in a patient with familial partial lipodystrophy. J Clin Endocrinol Metab. 2002 Jan;87(1):408-11. PMID:11788685
4. ↑ Gorla-Bajszczak A, Juge-Aubry C, Pernin A, Burger AG, Meier CA. Conserved amino acids in the ligand-binding and tau(i) domains of the peroxisome proliferator-activated receptor alpha are necessary for heterodimerization with RXR. Mol Cell Endocrinol. 1999 Jan 25;147(1-2):37-47. PMID:10195690
5. ↑ Harish S, Ashok MS, Khanam T, Rangarajan PN. Serine 27, a human retinoid X receptor alpha residue, phosphorylated by protein kinase A is essential for cyclicAMP-mediated downregulation of RXRalpha function. Biochem Biophys Res Commun. 2000 Dec 29;279(3):853-7. PMID:11162439 doi:10.1006/bbrc.2000.4043
6. ↑ Tsutsumi T, Suzuki T, Shimoike T, Suzuki R, Moriya K, Shintani Y, Fujie H, Matsuura Y, Koike K, Miyamura T. Interaction of hepatitis C virus core protein with retinoid X receptor alpha modulates its transcriptional activity. Hepatology. 2002 Apr;35(4):937-46. PMID:11915042 doi:10.1053/jhep.2002.32470
7. ↑ Santos NC, Kim KH. Activity of retinoic acid receptor-alpha is directly regulated at its protein kinase A sites in response to follicle-stimulating hormone signaling. Endocrinology. 2010 May;151(5):2361-72. doi: 10.1210/en.2009-1338. Epub 2010 Mar , 9. PMID:20215566 doi:10.1210/en.2009-1338
8. ↑ Kalkhoven E, Valentine JE, Heery DM, Parker MG. Isoforms of steroid receptor co-activator 1 differ in their ability to potentiate transcription by the oestrogen receptor. EMBO J. 1998 Jan 2;17(1):232-43. PMID:9427757 doi:10.1093/emboj/17.1.232
9. ↑ Onate SA, Tsai SY, Tsai MJ, O'Malley BW. Sequence and characterization of a coactivator for the steroid hormone receptor superfamily. Science. 1995 Nov 24;270(5240):1354-7. PMID:7481822
10. ↑ Hayashi Y, Ohmori S, Ito T, Seo H. A splicing variant of Steroid Receptor Coactivator-1 (SRC-1E): the major isoform of SRC-1 to mediate thyroid hormone action. Biochem Biophys Res Commun. 1997 Jul 9;236(1):83-7. PMID:9223431 doi:10.1006/bbrc.1997.6911
11. ↑ Spencer TE, Jenster G, Burcin MM, Allis CD, Zhou J, Mizzen CA, McKenna NJ, Onate SA, Tsai SY, Tsai MJ, O'Malley BW. Steroid receptor coactivator-1 is a histone acetyltransferase. Nature. 1997 Sep 11;389(6647):194-8. PMID:9296499 doi:10.1038/38304
12. ↑ Jenster G, Spencer TE, Burcin MM, Tsai SY, Tsai MJ, O'Malley BW. Steroid receptor induction of gene transcription: a two-step model. Proc Natl Acad Sci U S A. 1997 Jul 22;94(15):7879-84. PMID:9223281
13. ↑ Liu Z, Wong J, Tsai SY, Tsai MJ, O'Malley BW. Steroid receptor coactivator-1 (SRC-1) enhances ligand-dependent and receptor-dependent cell-free transcription of chromatin. Proc Natl Acad Sci U S A. 1999 Aug 17;96(17):9485-90. PMID:10449719
14. ↑ Litterst CM, Kliem S, Marilley D, Pfitzner E. NCoA-1/SRC-1 is an essential coactivator of STAT5 that binds to the FDL motif in the alpha-helical region of the STAT5 transactivation domain. J Biol Chem. 2003 Nov 14;278(46):45340-51. Epub 2003 Sep 3. PMID:12954634 doi:http://dx.doi.org/10.1074/jbc.M303644200
15. ↑ Mukherjee R, Jow L, Croston GE, Paterniti JR Jr. Identification, characterization, and tissue distribution of human peroxisome proliferator-activated receptor (PPAR) isoforms PPARgamma2 versus PPARgamma1 and activation with retinoid X receptor agonists and antagonists. J Biol Chem. 1997 Mar 21;272(12):8071-6. PMID:9065481
16. ↑ Yin Y, Yuan H, Wang C, Pattabiraman N, Rao M, Pestell RG, Glazer RI. 3-phosphoinositide-dependent protein kinase-1 activates the peroxisome proliferator-activated receptor-gamma and promotes adipocyte differentiation. Mol Endocrinol. 2006 Feb;20(2):268-78. Epub 2005 Sep 8. PMID:16150867 doi:10.1210/me.2005-0197
17. ↑ Park SH, Choi HJ, Yang H, Do KH, Kim J, Lee DW, Moon Y. Endoplasmic reticulum stress-activated C/EBP homologous protein enhances nuclear factor-kappaB signals via repression of peroxisome proliferator-activated receptor gamma. J Biol Chem. 2010 Nov 12;285(46):35330-9. doi: 10.1074/jbc.M110.136259. Epub 2010, Sep 9. PMID:20829347 doi:10.1074/jbc.M110.136259