The Journal of biological chemistryJun 7, 2023

Obesity-related metabolic imbalance changes CtBP2 to reduce PPAR-alpha gene activity

Updated Feb 27, 2026

Abstract

CtBP2 interacts with PPARα, repressing its activity, especially in the context of obesity.

CtBP2 is a transcriptional corepressor that senses metabolites and interacts with PPARα, a key regulator of fatty acid breakdown.
The interaction between CtBP2 and PPARα is enhanced by malonyl-CoA, a metabolite that increases in obesity and inhibits fatty acid oxidation.
Mutations in CtBP2 that promote a monomeric form increase its interaction with PPARα.
Reducing malonyl-CoA levels decreases the formation of the CtBP2-PPARα complex.
In obese livers, the interaction between CtBP2 and PPARα is accelerated, while removing CtBP2 leads to increased activation of PPARα target genes.

Simplified

Maintenance of metabolic homeostasis is secured by metabolite-sensing systems, which can be overwhelmed by constant macronutrient surplus in obesity. Not only the uptake processes but also the consumption of energy substrates determine the cellular metabolic burden. We herein describe a novel transcriptional system in this context comprised of peroxisome proliferator-activated receptor alpha (PPARα), a master regulator for fatty acid oxidation, and C-terminal binding protein 2 (CtBP2), a metabolite-sensing transcriptional corepressor. CtBP2 interacts with PPARα to repress its activity, and the interaction is enhanced upon binding to malonyl-CoA, a metabolic intermediate increased in tissues in obesity and reported to suppress fatty acid oxidation through inhibition of carnitine palmitoyltransferase 1. In line with our preceding observations that CtBP2 adopts a monomeric configuration upon binding to acyl-CoAs, we determined that mutations in CtBP2 that shift the conformational equilibrium toward monomers increase the interaction between CtBP2 and PPARα. In contrast, metabolic manipulations that reduce malonyl-CoA decreased the formation of the CtBP2-PPARα complex. Consistent with these in vitro findings, we found that the CtBP2-PPARα interaction is accelerated in obese livers while genetic deletion of CtBP2 in the liver causes derepression of PPARα target genes. These findings support our model where CtBP2 exists primarily as a monomer in the metabolic milieu of obesity to repress PPARα, representing a liability in metabolic diseases that can be exploited to develop therapeutic approaches.

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Abstract

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