Slanted Science

For several years, scientists have known that, at least in organisms such as flies and mice, liefspans can be significantly increased by restricting the animals’ protein intake. The mechanism(s) behind this are currently unknown, but a new piece of research suggests the involvement of mitochondria.

Protein-restricted diets increase transcription of life-extending genes (that is, turning the DNA messages into an intermediate form which can then go on to become an active protein). A lot of previous research has been targeted at working out how those genes are switched on to increase transcription. What Pankaj Kapahi and colleagues have done is to focus on the second step: translation (turning the intermediate into active, life-extending protein).

**Quick Note: to find out more about transcription, translation, proteins, genes, and loads more, you will soon be able to visit the SlantedScience tutorials pages. If you’d like to receive notification when these go online, please email me at PaulGibson@SlantedScience.com**

The work was carried out at California’s Buck Institute for Age Research, and looked at what kinds of proteins were being increased by these diets. The answer: proteins which help sustain mitochondrial health. Mitochondria are organelles which exist in almost every cell, and are responsible for producing the energy each cell needs to sustain itself.

Mitochondria become less efficient as animals age, leading to older cells not being able to generate enough energy to keep themselves going. This study has shown that restricting dietary protein causes cells to produce certain proteins known to positively affect mitochondrial function. Kapahi and pals then mutated some of these beneficial proteins in their fruit flies, and found that flies lacking the genes no longer gained any benefits from a low-protein diet.

In particular, the group positively identified 4E-BP as important in the process. 4E-BP has been called a “metabolic brake”; its function is to signal to the cell that it should reduce its global protein output during times of stress. However, this study shows that, in flies with the low-protein diet, 4E-BP actually causes the beneficial mitochondrial proteins to be expressed more. 4E-BP, and its upstream regulators, would seem to interesting targets for further exploration in lifespan extension research.

In the meantime, expect to see Simon Cowell munching on a lot more vegetables.

Don’t Hold Your Breath, But This May Lead To: a more widespread uptake of (mostly) vegetarian diets. And the huge associated benefits of globally reduced animal rearing.