8u57
PPARg LBD in complex with perfluorooctanoic acid (PFOA)
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 PubMedPerfluorooctanoic acid (PFOA) is a widespread environmental pollutant of the perfluoroalkyl substance (PFAS) class that is extremely resistant to environmental and metabolic degradation, leading to bioaccumulation. PFOA exposure has been linked to many health effects including endocrine disruption and metabolic dysregulation, but our understanding of the molecular mechanisms resulting in these outcomes remains incomplete. One target affected by PFOA is the ligand regulated nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma) which plays a critical role in controlling metabolic homeostasis through regulating processes such as adipogenesis, glucose homeostasis, inflammation and osteogenesis. It has been previously established that PFOA activates PPARgamma through binding to the PPARgamma ligand binding domain (PPARgamma LBD) leading to increased expression of PPARgamma controlled target genes. However, the mechanism by which PFOA achieves this has remained elusive. Here, we employed a combination of X-ray crystallography and fluorescence polarization assays to provide a structural basis for PFOA mediated activation of PPARgamma via binding to the PPARgamma LBD. Using X-ray crystallography, the cocrystal structure of the PPARgamma LBD:PFOA complex was solved. This revealed that PFOA occupies three distinct sites, two within the PPARgamma LBD and one within the activation function 2 (AF2) on the protein surface. Structural comparison of PFOA binding with previously reported PPARgamma:ligand complexes supports that PFOA activates PPARgamma by a partial agonist mechanism at micromolar concentrations. Fluorescence polarization assays also revealed that PFOA binding to the AF2 is unlikely to occur in a cellular context and confirmed that PFOA behaves as a partial agonist in vitro, weakly recruiting a coactivator peptide to the AF2 of the PPARgamma LBD. This discovery provides an advancement in understanding PFOA mediated regulation of PPARgamma, giving new insight regarding regulation of PPARgamma by PFAS and PFAS substitutes in general and can be applied to the design and assessment of safer PFAS. A structural basis for the activation of peroxisome proliferator-activated receptor gamma (PPARgamma) by perfluorooctanoic acid (PFOA).,Pederick JL, Frkic RL, McDougal DP, Bruning JB Chemosphere. 2024 Apr;354:141723. doi: 10.1016/j.chemosphere.2024.141723. Epub , 2024 Mar 15. PMID:38494006[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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