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A discussion of every disease caused by modification of the various apoptotic pathways would be impractical, but the concept overlying each one is the same: The normal functioning of the pathway has been disrupted in such a way as to impair the ability of the cell to undergo normal apoptosis.
Overview of signal transduction pathways involved in apoptosis. Cell death is the event of a biological cell ceasing to carry out its functions. This may be the result of the natural process of old cells dying and being replaced by new ones, as in programmed cell death, or may result from factors such as diseases, localized injury, or the death of the organism of which the cells are part.
It is one of the main types of programmed cell death (PCD) and involves a series of biochemical events leading to a characteristic cell morphology and death. Extrinsic apoptotic pathways: Occur when factors outside the cell activate cell surface death receptors (e.g., Fas) that result in the activation of caspases-8 or -10. [10]
Once the apoptosome was established as the procaspase-9 activator, mutations within this pathway became an important research area. Some examples include human leukemia cells, ovarian cancer and viral infections. [8] [9] [10] Current research areas for this pathway will be discussed in further detail. There are hidden routes for cell death as ...
There are another two proteins worth mentioning that inhibit the release of cytochrome c in the mitochondria. Bcl-2 and Bcl-xl are anti-apoptotic and therefore prevent cell death. There is a potential mutation that can occur in that causes the overactivity of Bcl-2. It is the translocation between chromosomes 14 and 18.
During apoptosis, a cell goes through a series of steps as it eventually breaks down into apoptotic bodies, which undergo phagocytosis.In the context of karyorrhexis, these steps are, in chronological order, pyknosis (the irreversible condensation of chromatin), karyorrhexis (fragmentation of the nucleus and condensed DNA) and karyolysis (dissolution of the chromatin due to endonucleases).
Even after the initial cause of the necrosis has been halted, the necrotic tissue will remain in the body. The body's immune response to apoptosis, which involves the automatic breaking down and recycling of cellular material, is not triggered by necrotic cell death due to the apoptotic pathway being disabled. [29]
It is proposed that both pyroptosis and necroptosis may act as defence systems against pathogens when apoptotic pathways are blocked. [ citation needed ] Summary of the different morphologies, mechanisms and outcomes of three most well-characterized forms of cell death (apoptosis, pyroptosis, and necrosis) [ 10 ] [ 6 ] [ 17 ]