Protein Bax: Reveal One Potential Mechanism of Cell Death
The left picture shows the main researchers of this finding; the right picture shows the visualization of the molecular changes in protein Bax
Cell death, or apoptosis, is an important factor in controlling the number of cells in the body. Proper cell numbers ensure our health condition; over or insufficient is not good. Once there are defects in cell death, our health would be affected. For example, insufficient cell death can cause cancer by allowing cells to become immortal, while excessive cell death of neurons may be a cause of neurodegenerative conditions.
Scientists have for the first time visualized the molecular changes in a critical cell death protein that force cells to die. The protein is Bax.
Previous studies have known that the activation of the protein Bax could lead to apoptosis, but the activation mechanism is not clear.
One of the critical procedures in apoptosis is that holes are punched into the mitochondrial membrane. Once this happens the cell is going to go on and die. Bax is responsible for punching the holes in the mitochondrial membrane.
Using the Australian Synchrotron, scientists can obtain detailed three-dimensional images of Bax changing shape as it moved from its inactive to active form. Bax is activated when small protein fragments called BH3-peptides bind to it. These peptides open up the Bax molecule like a key unlocking a padlock. This unlocked form of Bax can bind to another Bax molecule, which can then form larger Bax complexes that can go on to break up membranes in the cell. The active form ruptures mitochondrial membranes, removing the cell's energy supply and causing cell death.
Visualizing its activation brings us a step closer to understanding the mechanics of cell death. The finding provides important insights into how cell death occurs, and could lead to new classes of medicines that control whether diseased cells live or die.
Tags: Protein Bax, Apoptosis, Molecular Change, Activation Mechanism