The retinoic acid receptor (RAR) is a type of nuclear receptor that binds to retinoic acid, a metabolite of vitamin A. RAR plays a crucial role in regulating gene expression, influencing processes such as cell growth, differentiation, and development. It is essential for normal embryonic development and is involved in various physiological functions throughout life. RAR exists in three main subtypes: RARα, RARβ, and RARγ, each encoded by different genes. These receptors can form heterodimers with other proteins, such as retinoid X receptors (RXR), to enhance their regulatory effects. Dysregulation of RAR signaling is associated with several diseases, including certain types of cancer.