Mutations within apoptosis gene and caspases

Apoptotic-mediated cell death is an important and remarkable survival system for organisms because it removes disrupted cells of the body. Mutation can also act as a survival method for removing the damaged cells in multicellular and also unicellular organisms, when damaged DNA parts (lesions) are not removed. In a normal healthy body, damage that occurs in DNA is repaired by original DNA repair systems including the cellular responses such as fixing of the normal base pair sequence and structure of damaged DNA. When the DNA damage cannot be repaired, the cells either survive by dealing with the lesion (damaged part), or undergo cell death, which is known as apoptosis. Caspases are a family of cysteine proteases acting as potent effectors during apoptosis to alter most cellular structures, including the cytoskeleton, cell junctions, mitochondria, endoplasmic reticulum, Golgi, and the nucleus by the process k/a proteolysis, which includes breakdown of proteins into smaller polypeptides or amino acids. These play a major role in the initiation and execution of programmed cell death. Caspases exist as inactive zymogens (an inactive substance that is converted into an enzyme when activated by another enzyme) in cells and undergo a series of catalytic activation at the start of apoptosis. The activated caspases give an inhibition function by the inhibitor-of-apoptosis (IAP) family of proteins. The inactivation of programmed cell death has very harmful effects not only on the development but also on the overall functioning of multicellular organisms. Apart from developmental abnormalities, it may lead to tumorigenesis, and other serious health problems. Unregulated apoptosis may also be the leading cause of cancer therapy chemoresistance.