Our cells die and replenish themselves all of the time, but cells do not have the ability to do this forever. The ends of chromosomes, called telomeres, become shorter and shorter every time our cells divide. When telomeres become too short, the cells can no longer divide to replenish old cells. When this happens, our organs and our bodies begin to age. However, there is an enzyme, called telomerase that reconstructs these telomeres, allowing for cells to continue replicating.
Recently, researchers at the Salk Institute, including Vicki Lunblad and Timothy Tucey have discovered that there is an “on/off switch” that turns off telomerase even when it is present in cells. They discovered this by watching the activity of telomerase during cell replication. Once the DNA has been replicated, telomerase acquires a key subunit allowing it to be activated. However very soon after this activation, telomerase disassembles itself, turning it “off.” This allows telomerase to be kept at low levels in the cell. A low level of telomerase is necessary because when there is too much telomerase, cells continuously divide and grow causing cancer.
By studying how this “on/off switch” regulates telomerase, scientist may be able to slow down the shortening of telomeres by manipulating this kind of regulation. This would allow healthy cells may continue dividing and could ultimately lead to treatments of diseases caused by old age.
Reference:
Salk Institute for Biological Studies. "On/off switch for aging cells discovered by scientists." ScienceDaily. ScienceDaily, 20 September 2014.
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