RARα, or Retinoic Acid Receptor Alpha, is a protein that plays a crucial role in the body's response to retinoic acid, a derivative of vitamin A. It functions as a transcription factor, meaning it helps regulate the expression of specific genes involved in various biological processes, including cell growth, differentiation, and development. This receptor is part of a larger family of nuclear receptors that interact with hormones and other signaling molecules. RARα is particularly important in processes like embryonic development and the immune response, and it has been studied for its implications in conditions such as cancer and neurodegenerative diseases.