Apoptosis is a process of programmed cell death that occurs in multicellular organisms. It is a highly regulated and controlled process that is essential for normal development, tissue homeostasis, and elimination of damaged or infected cells. The word “apoptosis” comes from the Greek word “apoptosis,” which means “falling off,” and refers to the process by which cells shrink and their components are broken down into small apoptotic bodies that can be safely engulfed and eliminated by phagocytes.
During apoptosis, a variety of intracellular signals can trigger a cascade of biochemical events that lead to the activation of a family of proteases called caspases, which cleave various cellular proteins, resulting in the breakdown of the cell’s cytoskeleton, nucleus, and organelles. The apoptotic cell also displays characteristic changes in its plasma membrane, such as the exposure of phosphatidylserine on the outer surface of the membrane, which serves as an “eat-me” signal for phagocytes.
Apoptosis plays a critical role in development, as it is responsible for sculpting and shaping organs and tissues, as well as eliminating excess or damaged cells. It also plays a critical role in the immune system, where it is used to eliminate infected or cancerous cells. Dysregulation of apoptosis has been implicated in a variety of diseases, including cancer, autoimmune disorders, and neurodegenerative diseases.