Identification and Molecular Characterization of Peroxisome Proliferator-Activated Receptor ? as a Novel Target for Covalent Modification by 15-Deoxy-?12,14-prostaglandin J2.

ABSTRACT: PPAR? belongs to the peroxisome proliferator-activated receptor (PPAR) family of nuclear receptors. Upon activation by an agonist, PPAR? controls a variety of physiological processes via regulation of its target genes. 15-Deoxy-?12,14-prostaglandin J2 (15d-PGJ2) is a cyclopentenone prostaglandin that features an electrophilic, ?,?-unsaturated ketone (an enone) in the cyclopentenone ring. Many of 15d-PGJ2's biological effects result from covalent interaction between C9 and the thiol group of a catalytic cysteine (Cys) in target proteins. In this study, we investigated whether 15d-PGJ2 activates PPAR? by forming a covalent adduct. Our data show that 15d-PGJ2 activates PPAR?'s transcriptional activity through formation of a covalent adduct between its endocyclic enone at C9 and Cys249 in the receptor's ligand-binding domain. As expected, no adduct formation was seen following a Cys-to-Ser mutation at residue 249 (C249S) of PPAR? or with a PGD2/PGJ2 analogue that lacks the electrophilic C9. Furthermore, the PPAR? C249S mutation weakened induction of the receptor's DNA binding activity by 15d-PGJ2, which highlights the biological significance of our findings. Calculated chemical properties as well as data from molecular orbital calculations, reactive molecular dynamics simulations, and intrinsic reaction coordinate modeling also supported the selectivity of 15d-PGJ2's C9 toward PPAR?'s Cys thiol. In summary, our results provide the molecular, chemical, and structural basis of 15d-PGJ2-mediated PPAR? activation, designating 15d-PGJ2 as the first covalent PPAR? ligand to be identified.

SUBMITTER: Reddy AT 

PROVIDER: S-EPMC6470001 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature