- Cell undergoes programmed cell death where cell components are orderly disposed of
- Cell shrinks and then lysosomes’ hydrolytic proteins (proteases, amylases [carbs], nucleases, etc.) fragment DNA and organelles that are packaged vesicles digested by white blood cells
- Caspases: main proteases, enzymes that cut up proteins and carry out apoptosis.
Reasons
- Allow for the normal development and maintenance of an organism by selectively killing infected, damaged, or finished cells in an orderly way so dying cell doesn’t leak digestive enzymes
- DNA damage (mutation) in nucleus
- Release of extracellular death signal that binds to receptor and initiates phosphorylation cascade that activates nucleases (nucleic acids) and proteases (protein) that break down the cell
- Protein misfolding in the nucleus (ex. alzheimers)
- Mutations cause cancer, so apoptosis helps prevent this
Regulation
- Ced-9 prevents apoptosis by inhibiting caspases