Today's Nobel Prize in Medicine has been awarded to Japan's Yoshinori Ohsumi for his work in understanding a fundamental biological process in which the cell digests damaged or unneeded components. Termed "autophagy," or self-eating, the process allows cells to survive periods of stress or starvation or to adapt to changing conditions or needs. Failures in autophagy have been linked to both cancer and neurodegenerative diseases.
As with many past winners, Ohsumi seems to have had the right ideas at the right time. In the 1950s, earlier Nobel winner Christian de Duve identified small structures inside cells that carried lots of digestive enzymes. Others recognized that these structures were involved in situations where cells digested parts of their own internal membranes, liberating raw materials to be reused. A decade later, the term autophagy was coined, and people recognized that it was a normal process within cells.
But over the following decades, progress on understanding how it worked was slow, in part because typical complex, eukaryotic cells are filled with small bits of membrane, and partly because the process was transient, rapidly digesting the material it was fed. We knew it was occurring, but we didn't know when or how it was triggered. This left the field open to Ohsumi, who started working on it in the 1990s.