7e2o
From Proteopedia
X-ray Crystal structure of PPARgamma R288H mutant.
Structural highlights
DiseasePPARG_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. FunctionPPARG_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] Publication Abstract from PubMedPeroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor and the molecular target of thiazolidinedione-class antidiabetic drugs. It has been reported that the loss of function R288H mutation in the human PPARgamma ligand-binding domain (LBD) may be associated with the onset of colon cancer. A previous in vitro study showed that this mutation dampens 15-deoxy-Delta(12,14)-prostaglandin J2 (15d-PGJ2, a natural PPARgamma agonist)-dependent transcriptional activation; however, it is poorly understood why the function of the R288H mutant is impaired and what role this arginine (Arg) residue plays. In this study, we found that the apo-form of R288H PPARgamma mutant displays several altered conformational arrangements of the amino acid side chains in LBD: 1) the loss of a salt bridge between Arg288 and Glu295 leads to increased helix 3 movement; 2) closer proximity of Gln286 and His449 via a hydrogen bond, and closer proximity of Cys285 and Phe363 via hydrophobic interaction, stabilize the helix 3-helix 11 interaction; and 3) there is steric hindrance between Cys285/Gln286/Ser289/His449 and the flexible ligands 15d-PGJ2, 6-oxotetracosahexaenoic acid (6-oxoTHA), and 17-oxodocosahexaenoic acid (17-oxoDHA). These results suggest why Arg288 plays an important role in ligand binding and why the R288H mutation is disadvantageous for flexible ligand binding. Structural Insights into the Loss-of-Function R288H Mutant of Human PPARgamma.,Egawa D, Ogiso T, Nishikata K, Yamamoto K, Itoh T Biol Pharm Bull. 2021;44(9):1196-1201. doi: 10.1248/bpb.b21-00253. PMID:34471047[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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