Apoptosis: Reaper protein is another key to the process of cell death
New information about apoptosis has been obtainedAlexander Shuster, sci-lib.com based on the materials of Science News:
'Reaper' Protein Strikes at Mitochondria to Kill CellsThe cells of the human body, roughly speaking, are constantly on the verge of suicide.
A huge number of protein molecules control the state of cells, preventing or triggering programmed cell death. Programmed cell death, also known as apoptosis, is a mechanism that can prevent the development of neoplasms. Unfortunately, apoptosis can cause harm to the human body. For example, a violation of control over this process can initiate the death of brain neurons.
Stages of cell death during apoptosisResearchers from Rockefeller University decided to investigate the process of apoptosis in detail.
Scientists hope that a deeper study of the mechanism of programmed cell death will allow us to obtain results that will teach doctors how to manipulate the process of apoptosis – artificially initiate the death of cells dangerous to human health and prevent the death of cells necessary for the body. During the scientific work, the authors of the studies studied in detail a protein called Reaper. This protein was first described in 1994 in the journal "Science". Under normal conditions, Reaper interacts with apoptosis protein inhibitor (IAPs) molecules. These proteins prevent the development of a chain of reactions necessary for cell death. Reaper, interacting with inhibitors of apopotosis proteins, deprives them of the necessary activity and thereby contributes to the development of the above chain of reactions.
The authors of the research specify that the Reaper protein is a kind of harbinger of cell death. But Reaper does not kill cells, but serves as the key to triggering apoptosis. The Reaper protein and other drosophila IAPs antagonists (Hid and Grim) are involved in triggering a chain of programmed cell death reactions in the body of fruit flies. Until now, it was not known exactly where and how the Reaper protein initiates the development of apoptosis. In order to find out, scientists have grown genetically modified fruit flies, in whose body various variants of Reaper proteins present in the eyes of experimental insects were synthesized. This allowed scientists to assess the contribution of various protein variants to the development of apoptotic cell death. During the study, a domain was discovered that is responsible for the formation of complexes with the Reaper protein. This domain can be modified to increase the activity of the Reaper. The activity of Reaper proteins was assessed by the degree of damage that was done to the eyes of fruit flies.
It was found that the Reaper must be in the mitochondria in order to initiate the process of apoptosis. The Reaper protein enters the mitochondria using the Hid protein. Using special equipment, scientists were able to fix the Reaper-Hid protein complex. It turned out that this complex is protected from degradation at the moment when the cell begins to die. Thus, the scientists concluded that the Hid protein and the Reaper protein interact closely during the initiation of programmed cell death. And their presence in mitochondria is a critical prerequisite for the initiation of apoptosis. The authors of the studies believe that the data they have obtained will help improve the treatment of neoplasms.
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