Inside every fruit fly cell are tiny power plants called mitochondria. They generate energy, but in the process damaged proteins pile up, like trash on a factory floor. If the trash is never cleared, the factory starts running worse, and this is tied to aging.
Scientists set out to boost the cleanup crew in the mitochondria. To do it, they switched on two genes in the flies that together build the ClpXP complex. This complex works like a shredder: it unfolds a damaged protein and cuts it into pieces. When the cleanup crew was switched on too strongly, the power plants suffered. So the researchers dialed the power down, and it turned out that female flies lived 9% longer than their sisters without the genes switched on.
Interestingly, the cleanup crew did not set off an alarm signal in the cell. Normally, when proteins are damaged, mitochondria launch a stress response, but that did not happen here. This means the benefit of the cleanup works through another pathway, which has yet to be studied. For now this is knowledge about the mechanisms of aging, but it shows that mitochondrial cleanup crews could become a target for drugs that slow aging.
The ClpXP complex consists of 14 ClpP subunits forming a barrel and 6 ClpX subunits working as an ATP-dependent unfolding machine. In fruit flies and humans, there are about 25 resident proteases in mitochondria, but ClpXP is considered one of the main quality controllers.
In Greg Egan's novel Permutation City, characters manipulate cellular processes to achieve immortality; the idea of targeted protease activation for lifespan extension echoes such an engineering approach to aging.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.