RXRA (retinoid X receptor alpha) is a ligand-activated nuclear receptor and transcription factor that functions as a critical regulator of gene expression across multiple biological pathways 1. RXRA forms homo- or heterodimers with retinoic acid receptors (RARs) and other nuclear receptors, binding to retinoic acid response elements (RARE) upon ligand binding (9-cis retinoic acid being the high-affinity ligand) to activate or repress target gene transcription 1. In the absence of ligand, RXRA-containing complexes recruit transcriptional corepressors and histone deacetylases; ligand binding triggers corepressor dissociation and coactivator recruitment 1. RXRA serves as a common heterodimeric partner for multiple nuclear receptors including RARA and PPARA, regulating diverse processes including fatty acid metabolism, vascular homeostasis, and immune responses 23. Disease relevance spans multiple conditions: RXRA variants influence Alzheimer's disease risk and cholesterol metabolism 4, while RXRA is a key target in triple-negative breast cancer therapy through the HDAC5/RXRA/ASNS axis 5. RXRA also mediates vascular normalization after anti-angiogenesis therapy in lung adenocarcinoma via retinoic acid metabolism in pericytes 3. Clinical significance includes potential pharmacological targeting—UBR5 inhibition modulates RXRA degradation affecting therapeutic efficacy 1—and genetic polymorphisms predicting levothyroxine dosage requirements in hypothyroid patients 6. These findings establish RXRA as a central node in metabolic, oncologic, and neurodegenerative disease pathways.