| Structural highlights
Disease
[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. [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.
Function
[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.[4] [5] [6] [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.[7] [8] [9] [10] [11] [12] [13]
Publication Abstract from PubMed
The recent discovery that PPARg targeted anti-diabetic drugs function by inhibiting Cdk5 mediated phosphorylation of the receptor has provided a new viewpoint to evaluate and perhaps develop improved insulin sensitizing agents. Herein we report the development of novel thiazolidinediones that retain similar anti-diabetic efficacy as rosiglitazone, yet do not elicit weight gain or edema, common side effects associated with PPARg activation. Further characterization of one these compounds show GQ-16 to be an effective inhibitor of Cdk5 phosphorylation of PPARg. The structure of GQ-16 bound to PPARg demonstrates that the compound utilizes a binding mode distinct from other reported PPARg ligands, although it does share structural features with other partial agonists such as MRL-24 and PA-082 that have similarly been reported to dissociate insulin sensitization from weight gain. Hydrogen-deuterium exchange studies reveal that GQ-16 strongly stabilizes the beta-sheet region of the receptor, presumably explaining the compounds efficacy in inhibiting Cdk5 phosphorylation of S273. Molecular dynamics simulations affirm the partial agonist activity of GQ-16 indicating that the compound prevents helix 12 from docking efficiently in the active conformation. Our results here suggest that the emerging model, whereby "ideal" PPARg-based therapeutics stabilize the beta-sheet/S273 region and inhibit Cdk5 phosphorylation while minimally invoking adipogenesis and classical agonism, is indeed a valid framework to develop improved PPARg modulators that retain anti-diabetic actions while minimizing untoward effects.
GQ-16, A novel PPARgamma ligand, promotes insulin sensitization without weight gain.,Amato AA, Rajagopalan S, Lin JZ, Carvalho BM, Figueira AC, Lu J, Ayers SD, Mottin M, Silveira RL, Souza PC, Mourao RH, Saad MJ, Togashi M, Simeoni LA, Abdalla DS, Skaff MS, Polikarpov I, Lima MC, Galdino SL, Brennan RG, Baxter JD, Pitta IR, Webb P, Phillips KJ, Neves FA J Biol Chem. 2012 May 14. PMID:22584573[14]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ 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
- ↑ Amato AA, Rajagopalan S, Lin JZ, Carvalho BM, Figueira AC, Lu J, Ayers SD, Mottin M, Silveira RL, Souza PC, Mourao RH, Saad MJ, Togashi M, Simeoni LA, Abdalla DS, Skaff MS, Polikarpov I, Lima MC, Galdino SL, Brennan RG, Baxter JD, Pitta IR, Webb P, Phillips KJ, Neves FA. GQ-16, A novel PPARgamma ligand, promotes insulin sensitization without weight gain. J Biol Chem. 2012 May 14. PMID:22584573 doi:10.1074/jbc.M111.332106
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