Switch that Controls Aging Identified in Worms

Their finding was reported in the December 11, 2001, issue of Current Biology.

The switch, known as DAF-16, is a protein that can either lengthen or shorten the lifespan in the eyelash-sized roundworm, C elegans. DAF-16 is a critical part of a complex signaling pathway that involves insulin and glucose. When it penetrates the nucleus, it seems to turn on a switch that lengthens the life of the roundworm. The switch is controlled by food availability, temperature, and stress. The researchers say a similar protein is likely found in humans.

Insulin released with glucose in humans rises and stores more fat when humans consume sugar, inhibiting DAF-16 to enter the nucleus. The same process is likely in animals. When DAF-16 is located in the cytoplasm of cells outside the nucleus, it is in the "off' mode. When the cell is seeking more food, DAF-16 enters the nucleus, triggering a cascade of biochemical events that lead to a longer lifespan.

According to the researchers, the longer-lived species of C elegans have a higher resistance to free radicals and environmental stress. They say there is a good possibility that a pharmaceutical could be developed that would trigger translocation of DAF-16 into the cell nucleus, causing organisms to lower their reproduction level and fight off the negative impact of free radicals.

"If DAF-16 is ‘on,' it triggers less reproduction, more efficient cell repair and longer lives,” noted Thomas Johnson, professor of psychology at the University of Colorado and a research associate. "On the other hand, if DAF-16 is ‘off,' the result is more reproduction, worse cell repair, and a shortened lifespan.





Related Links:
Univ. of Colorado