The last link in the chain
The final link has now been found for a signal chain in our body cells that leads to programmed cell death. The protein Apaf-3 could be isolated from cancer tissue. Apoptosis or programmed cell death is a vital process in our body. Cells that are no longer needed or are damaged make way for young tissue through their “suicide”. If there is an error in the signal chain that leads to apoptosis, this can have dire consequences: either too many cells die or too few. The consequences can be neurological dysfunction or even death of the whole organism.
In order to be able to effectively counteract diseases caused by faulty cell programs, scientists must know exactly which signal has to come at what time. A team from Dallas' UT Southwestern Medical Center led by Xiaodong Wang has now identified and purified the final link in the chain (cell dated November 14, 1997).
This is the Apaf-3 protein. It is activated once it binds to cytochrome c, which is secreted by the mitochondria, and ATP, the cell's energy currency. Apaf-3 then triggers apoptosis. "We can use this information to trigger the signaling chain, especially in cancer cells," says Wang.
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