Calcium is a mineral that's important for the function of every cell in the body. Because calcium can serve as a chemical signal in cells, its levels are carefully regulated. One intriguing role for calcium is its ability to trigger a process known as apoptosis, which is a controlled form of cell death.
Apoptosis
Apoptosis is a process by which cells can die in a controlled way. The death of cells in response to certain stimuli is an important part of physiology; for example, apoptosis of cells in between the fingers during fetal development allows for the disappearance of "webbed" hands. Apoptosis is also critical for cells that have become damaged or dysfunctional, as it allows the cells to die without releasing chemicals that trigger inflammation and damage to the surrounding healthy cells, the Reproductive and Cardiovascular Research Group explains.
Intracellular Calcium
Calcium has an electrical charge when dissolved in water-based solutions, such as the fluid inside of cells. Intracellular calcium levels are regulated by a structure known as the endoplasmic reticulum, where it is bound by various proteins. Your cells release some of the calcium from their endoplasmic reticulum in response to different chemical signals. Cells can also control intracellular calcium levels by controlling calcium transport into and out of cells.
Intracellular Calcium and Apoptosis
Changes of intracellular calcium levels are an important signal for apoptosis. The signal for apoptosis comes from a structure within cells known as the mitochondria. When cells become irreparably damaged or otherwise need to undergo apoptosis, the mitochondria release small amounts of a substance known as cytochrome c. The cytochrome c causes the endoplasmic reticulum to release its calcium, resulting in an increase in intracellular calcium, a 2003 article in "Nature Cell Biology" explains. This increase in calcium triggers other chemical changes, including the release of more cytochrome c, which induce apoptosis.
Advantages of This System
Apoptosis allows for the controlled destruction of cells in response to certain chemical signals, severe cellular or genetic damage, viral infection or when the cell becomes dysfunctional. One of the advantages of using intracellular calcium as a trigger for apoptosis is that it allows for changes in one part of the cell to affect the environment throughout the cell. Apoptosis must be coordinated in many different parts of the cell. Most cells have multiple mitochondria, which means that there are multiple sites in the cell that can recognize and initiate a process that needs to be synchronized throughout a much larger area to cause apoptosis to proceed.
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