Apoptosis is the genetically regulated form of cell death (programmed cell death) that permits the safe disposal of
cells when they are damaged or fulfilled their intended biological function. It is a vitally important process during
normal development and the adult life of humans and many living organisms. Apoptosis starts with death signals
coming from outside or inside of the cell. These signals activate two major apoptotic pathways; extrinsic/cell
surface death receptor and the intrinsic/mitochondrial pathways. During apoptosis a group of proteases are
activated which cause DNA fragmentation, cytoplasmic shrinkage and, membrane blebbing. Apoptotic cells
divide into apoptotic bodies and these apoptotic bodies are then removed from tissue by phagocytes and adjacent
cells.
In humans, dysregulation of apoptosis can result in malignant, autoimmune, and neurodegenerative diseases. The
understanding of the mechanisms controlling apoptosis seems important in these diseases and it may shed light
for new therapeutic endeavors.
Key words: apoptosis, death receptors, caspase, mitochondria.
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