A Look at the Inner Life of a Doomed Cell
Posted in Biology on March 28th, 2008 by MikeGeneOne of the major complaints about Harvard's "Inner Life of the Cell" video was that it was too serene and uncrowded, creating an "illusion" of design that did not exist. What I have for you below is another award-winning animation which factors for those complaints. It shows the crowded, chaotic, Brownian world of the cell. The process that is illustrated is apoptosis, otherwise known as programmed cell death.
Here's the walk through: You'll see a T lymphocyte approach a diseased cell and the animation will switch to the surface of the diseased cell. Welcome to chaos of the molecular world! You'll then see the lymphocyte present its death ligand to the death receptors of the cell, resulting in trimerization and thus activation. In essence, the self-destruct button has been pushed. Then, you'll switch to the cytoplasmic face of the death receptors which can now attach adaptor proteins, which in turn, fish out procaspase 8. The procaspase 8s become activated and break off to activate other caspase 3s in the cytoplasm "“ the signal is being amplified and spread. The caspase 3s will go about cleaving other cytoplasmic proteins. At this point, you'll switch to a lower magnification to watch the signal spread, causing mitochondria to release their cytochrome c. This protein, which is normally part of the life-giving electron transport chain needed to fuel of the ATP synthase will now moonlight as the a death signal, where it will bind to a protein called Apf1 triggering the formation of the the death wheel, which will then sequentially bind caspase 9s to form the apoptosome, which will activate an army of caspase 3s, reinforcing the signal from the death receptor. The activated caspases will begin the process of orderly taking the cell apart and the cleavage of part of the actin cytoskeleton is shown. Then you switch to a picture of the cell to show the result of the buzzing caspases "“ the cell breaks apart into many small vesicles known as apoptotic bodies. What is not shown is that phagocytotic cells will then simply eat these, providing for the clean removal of diseased or worn out cells.
Are you ready for the show?











