Apoptosis, or programmed cell death, is an adaptive form of cell death that plays a critical role in turnover of mitotic cells and various tissues in the adult, including epithelial cells, fibroblasts and various endocrine cells. Programmed cell death also plays a major role in development in organizing the body plan and molding intricate cellular structures such as nerve cell circuits in the brain. Rapidly progressing research into the molecular and biochemical underpinnings of the programmed cell death process are revealing novel genetic programs and molecular interactions that coordinate a...