A protein called Sestrin that serves as a natural inhibitor of aging and age-related pathologies in fruit flies has been identified by US scientists.
Researchers at the University of California, San Diego School of Medicine, also showed that Sestrin, whose structure and biochemical function are conserved between flies and humans, is needed for regulation of a signaling pathway that is the central controller of aging and metabolism.
The study has been conducted by Michael Karin, Distinguished Professor of Pharmacology in UCSD's Laboratory of Gene Regulation and Signal Transduction and lead author of the study.
Sestrins are highly conserved small proteins that are produced in high amounts when cells experience stress. Sestrin function, however, remained puzzling until the Karin group found that these proteins function as activators of AMP-dependent protein kinase (AMPK), and inhibitors of the Target of Rapamycin (TOR).
AMPK and TOR are two protein kinases that serve as key components of a signaling pathway shown to be the central regulator of aging and metabolism in a variety of model organisms, including the worm Caenorhabditis elegans, the fruit fly Drosophila melanogaster and mammals.
AMPK is activated in response to caloric restriction, a condition that slows down aging, whereas TOR is activated in response to over-nutrition, a condition that accelerates aging.
Activation of AMPK inhibits TOR, and drugs that activate AMPK or inhibit TOR can delay aging in several different model organisms including mammals.
The study has been published in the March 5 issue of the journal Science.