Retinoid X receptor alpha:Peroxisome proliferator-activated receptor alpha heterodimer (RXRα:PPARα)

The RXRα:PPARα heterodimer is a nuclear receptor complex formed by the association of Retinoid X receptor alpha (RXRα) and Peroxisome proliferator-activated receptor alpha (PPARα) [1.1.1]. This heterodimer acts as a ligand-dependent transcription factor that binds to specific DNA sequences known as Peroxisome Proliferator Response Elements (PPREs) to regulate the expression of genes involved in lipid and glucose metabolism [1.2.2]. It is considered a "permissive" heterodimer because it can be activated by ligands of either partner, such as fibrates for PPARα or rexinoids for RXRα, which often exhibit synergistic effects [1.3.2]. Biologically, the complex is essential for fatty acid oxidation, particularly in the liver and heart, and plays a significant role in modulating systemic inflammation and energy balance [1.3.1]. Dysregulation of this pathway is linked to metabolic diseases such as dyslipidemia, type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD) [1.2.1]. Consequently, the RXRα:PPARα heterodimer is a major therapeutic target for drugs aimed at lowering triglycerides and improving insulin sensitivity. However, clinical use of its agonists is associated with safety concerns, including potential hepatotoxicity and muscle-related toxicities like rhabdomyolysis [1.4.1, 1.4.2].

Other names

RXRα/PPARα complexNR2B1:NR1C1Retinoid X receptor alpha:Peroxisome proliferator-activated receptor alpha complexRXRA:PPARA heterodimer

The RXRα:PPARα heterodimer functions as a ligand-activated transcription factor that binds to Peroxisome Proliferator Response Elements (PPREs) in the promoter regions of target genes. Upon binding of agonists to either the PPARα or RXRα subunit, the complex undergoes a conformational change that facilitates the release of corepressors and the recruitment of coactivators, thereby initiating the transcription of genes primarily involved in fatty acid oxidation, lipid transport, and energy homeostasis [1.1.1, 1.2.1].