Aging cells may seal their fate by keeping worn-out proteins when they sprout offspring
Getting old means never letting go, a new study suggests.
Yeast, and possibly human cells, age at least in part because they hold on to broken-down proteins responsible for pumping out harmful chemicals and bringing in nutrients, researchers report in the August Nature Cell Biology. The finding could indicate that aging results both from a buildup of toxic substances, as researchers have previously suggested, and from a lack of essential nutrients.
Cells can replicate themselves only a finite number of times. For yeast cells that number is 20 to 30. But no one knows what sets the limit.
The new study suggests that a family of proteins known as multidrug resistance transporters is involved in determining how many times a cell can divide, and ultimately, how long an organism will live.