Retinoic Acid Binding consists of a biophysical interaction between retinoic acid (ligand) and a biological molecule, such as specific steroid receptor-like transcriptional regulator proteins containing an N-terminal modulating domain, a DNA-binding domain, and a C-terminal ligand-binding domain. The ligand-activated receptor complexes selectively bind as homodimers or heterodimers (with other steroid family receptors) to DNA response elements in target gene promoters, enhance transcriptional activity with coactivators, and mediate tissue growth and differentiation in embryogenesis, organogenesis, limb development, bone growth, and maintenance of normal epithelia. [ ]