Another Piece of the Calorie Restriction Puzzle
Researchers continue to follow the chained mechanisms by which calorie restriction confers health and longevity benefits. From EurekAlert!: "Previous research has shown that the lifespan-extending properties of dietary restriction are mediated in part by reduced signaling through TOR, an enzyme involved in many vital operations in a cell. When an organism has less TOR signaling in response to dietary restriction, one side effect is that the organism also decreases the rate at which it makes new proteins, a process called translation ... The big question then became what's happening in these translation-deficient cells to slow aging. That's when [we] had the idea to look at Gcn4 ... Gcn4 is a specialized protein called a transcription factor, which helps transfer genetic information during cell growth. The protein is activated when a cell is starving for amino acids. ... To make the link between Gcn4 and longevity, the scientists then asked whether preventing the increase of Gcn4 would block life span extension. In every case, cells lacking Gcn4 did not respond as strongly as Gcn4-positive cells. ... Although scientists don't yet know whether Gcn4 plays a similar role in organisms other than yeast, Kennedy points out that worms, flies, mice and humans all have Gcn4-like proteins that appear to be regulated in a similar way."
Link: http://www.eurekalert.org/pub_releases/2008-04/uow-rud041708.php