Japan's Yoshinori Ohsumi has won this year's Nobel Prize for medicine for his ground-breaking experiments with yeast. (Reuters)

Japanese biologist Yoshinori Ohsumi was awarded the 2016 Nobel Prize in medicine on Monday for discovering and elucidating a key mechanism in our body’s defense system that involves degrading and recycling parts of cells. Known as autophagy, this process plays an important role in cancer, Alzheimer’s, Type 2 diabetes, birth defects from Zika virus and numerous other devastating diseases.

In making the announcement, the prize committee in Stockholm said the work involves a series of “brilliant experiments” in the 1990s involving baker’s yeast that have helped explain how a cell, the smallest unit of life, adapts in response to stresses such as starvation and infection. In studying thousands of yeast mutants, Ohsumi identified 15 genes essential for autophagy. It turned out that virtually identical mechanisms exist in human cells as well.

“His discoveries opened the path to understanding the fundamental importance of autophagy in many physiological processes, such as in the adaptation to starvation or response to infection,” the Nobel committee wrote. “Mutations in autophagy genes can cause disease, and the autophagic process is involved in several conditions including cancer and neurological disease.”

Autophagy, which literally means “self-eating” in Greek, is a process of cell renewal that removes damaged proteins and organelles. When this process fails, it can speed up cell aging and causes diseases associated with aging. On the flip side, “too much” autophagy can promote growth of tumor cells in cancer and resistance to treatments.

Ohsumi, who is 71 and now serves as a professor emeritus at the Tokyo Institute of Technology, called the prize the “greatest source of joy and pride” for a scientist.

“Looking into bodily processes, I found that we have an ongoing renewal process without which living organisms can’t survive,” Ohsumi told NHK, the Japanese public broadcaster, shortly after the announcement. “This recycling process did not receive as much attention as it deserved, but I discovered that we should be paying more attention to this autophagy process,” he said, adding that he was “lucky” to make the discovery early on in his career.

The Nobel committee noted that “autophagy has been known for over 50 years.” However, its fundamental importance in physiology and medicine “was only recognized after Yoshinori Ohsumi’s paradigm-shifting research.” This amazing graph, which was displayed on a screen when the award was announced, shows just how much other work has been built on the discovery:

Last year’s Nobel Prize in medicine went to a trio of scientists for their work in parasitic diseases. William Campbell of the United States and Satoshi Omura of Japan helped develop a treatment that led to sharp decline in river blindness, and China’s Youyou Tu discovered the malaria drug artemisinin. In 2014, the award went to scientists John O’Keefe, May-Britt Moser and Edward I. Moser for deciphering the mechanism in the brain that allows us to find our way around. O’Keefe holds both U.S. and British citizenship, and the Mosers, a husband-and-wife team, are from Norway.

The award, established 115 years ago by industrialist Alfred Nobel, comes with a prize worth 8 million Swedish krona, or about $937,000.

Replay the announcement:

Fifield reported from Tokyo. This post has been updated.

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