The Fas receptor is a protein found on the surface of cells that plays a crucial role in regulating programmed cell death, also known as apoptosis. When the Fas receptor binds to its ligand, Fas ligand, it triggers a cascade of signals that lead to the self-destruction of the cell. This process is essential for maintaining healthy tissue and eliminating damaged or potentially harmful cells. In addition to its role in normal cell turnover, the Fas receptor is involved in immune system regulation. It helps control the activity of T cells, which are vital for the body's defense against infections and diseases. Dysregulation of the Fas receptor can contribute to various conditions, including autoimmune diseases and cancer.