Carl Zimmer in The New York Times:
Deep down, we are all cannibals. Our cells are perpetually devouring themselves, shredding their own complex molecules to pieces and recycling them for new parts. Many of the details of our endless self-destruction have come to light only in the past few years. And to the surprise of many scientists, links are now emerging between this inner cannibalism and diseases like Alzheimer’s disease and cancer.
“There’s been an explosion,” said Daniel Klionsky of the University of Michigan. “All of a sudden, researchers in different fields are seeing a connection.” In fact, as Dr. Klionsky wrote in a paper published online in Trends in Cell Biology, this cannibalism may extend our lifespan. Increasing our body’s ability to self-destruct may, paradoxically, let us live longer. Our cells build two kinds of recycling factories. One kind, known as the proteasome, is a tiny cluster of proteins. It slurps up individual proteins like a child sucking a piece of spaghetti. Once inside the proteasome, the protein is chopped up into its building blocks.