title: Alpha,beta-unsaturated ketone is a core moiety of natural ligands for covalent binding to peroxisome proliferator-activated receptor gamma.
abstract: Peroxisome proliferator-activated receptor gamma (PPARgamma) functions in various biological processes, including macrophage and adipocyte differentiation. Several natural lipid metabolites have been shown to activate PPARgamma. Here, we report that some PPARgamma ligands, including 15-deoxy-Delta12,14-prostaglandin J2, covalently bind to a cysteine residue in the PPARgamma ligand binding pocket through a Michael addition reaction by an alpha,beta-unsaturated ketone. Using rhodamine-maleimide as well as mass spectroscopy, we showed that the binding of these ligands is covalent and irreversible. Consistently, mutation at the cysteine residue abolished abilities of these ligands to activate PPARgamma, but not of BRL49653, a non-covalent synthetic agonist, indicating that covalent binding of the alpha,beta-unsaturated ketone in the natural ligands was required for their transcriptional activities. Screening of lipid metabolites containing the alpha,beta-unsaturated ketone revealed that several other oxidized metabolites of hydroxyeicosatetraenoic acid, hydroxyeicosadecaenoic acid, and prostaglandins can also function as novel covalent ligands for PPARgamma. We propose that PPARgamma senses oxidation of fatty acids by recognizing such an alpha,beta-unsaturated ketone as a common moiety.
authors.affiliation: Department of Molecular Biology, Biomolecular Engineering Research Institute, 6-2-3 Furuedai, Suita-City, Osaka 565-0874, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Shiraki
authors.forename: Narutoshi
authors.initials: N
authors.lastname: Kamiya
authors.forename: Sayaka
authors.initials: S
authors.lastname: Shiki
authors.forename: Takashi S
authors.initials: TS
authors.lastname: Kodama
authors.forename: Akira
authors.initials: A
authors.lastname: Kakizuka
authors.forename: Hisato
authors.initials: H
authors.lastname: Jingami
mesh_terms: D000818:Animals; D002460:Cell Line; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D007659:Ketones / Q000737:chemistry* / Q000378:metabolism*; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism*; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary
chemical_list: C097240:15-deoxy-delta(12,14)-prostaglandin J2; D005227:Fatty Acids; D007659:Ketones; D008024:Ligands; D047495:PPAR gamma; D015230:Prostaglandin D2