BioProtocols--Apoptosis1

What is apoptosis?

Apoptosis is a form of programmed cell death involving a serial of biochemical cascades including such proteins as Bcl-2, Bax, Apaf-1 or apoptotic protease activating factor-1, caspases such as caspase-9, caspase-3, and caspase-7, as well as proteins involved in digestion of proteins, degradation of DNA, and phagocytosis. Apoptosis is a normal cellular process and is essential for the proper development and maintenance of the tissues and organs. Apoptosis is also necessary for the destruction of cells considered a threat such as cells infected with viruses, cells with DNA damage, mutated cells, cancerous cells, and cells of the immune system after they have fulfilled their function. The decision of a cell to undergo apoptosis depends upon the balance between positive signals keeping the cell alive (eg, growth factors and interleukins such as IL-2) and negative signals that call for cellular suicide (eg,oxidative stress, DNA damage, improper protein folding, and specific molecules such as tumor necrosis factor alpha and beta (TNF-alpha and TNF-beta), and the FAS ligand (FasL) that binds to the Fas receptor, or CD95).