Year: 2022
Type: preprint
Abstract: The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) regulates transcription via two activation function (AF) regulatory domains: a ligand-dependent AF-2 coregulator interaction surface within the C-terminal ligand-binding domain (LBD), and an N-terminal disordered AF-1 domain (NTD or A/B region) that functions through poorly understood structural mechanisms. Here, we show the PPARγ AF-1 contains an evolutionary conserved Trp-Pro motif that undergoes cis/trans isomerization, populating two long-lived conformations that participate in intradomain AF-1 and interdomain interactions including two surfaces in the C-terminal LBD (β-sheet and the AF-2 surface), which are predicted in AlphaFold 3 models but not AlphaFold 2. NMR and chemical crosslinking mass spectrometry show that interdomain interactions occur for soluble isolated AF-1 and LBD proteins, as well as in full-length PPARγ in a phase separated state. Mutation of the region containing the Trp-Pro motif, which abrogates cis/trans isomerization of this region, impacts LBD interaction and reduces basal PPARγ transcription and agonist-dependent activation of PPARγ. Our findings provide structural insight into published in vitro and cellular studies that reported interdomain functional communication between the PPARγ AF-1 and LBD suggesting some of these effects may be mediated via AF-1/LBD interactions.
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
Funder: National Institutes of Health
OpenAlex ID: W4285394197