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Nobel Prize winner Yoshinori Ohsumi smiles as he speaks with Japanese Prime Minister Shinzo Abe on a mobile phone. (Shizuo Kambayashi/Associated Press)
Nobel Prize winner Yoshinori Ohsumi smiles as he speaks with Japanese Prime Minister Shinzo Abe on a mobile phone. (Shizuo Kambayashi/Associated Press)

Scientist who deduced secret of cell’s recycling system wins Nobel Prize Add to ...

A Japanese researcher whose decades of work in an underappreciated branch of cell biology allowed him to uncover one of life’s most fundamental processes has won this year’s Nobel Prize in physiology or medicine.

Yoshinori Ohsumi of the Tokyo Institute of Technology was recognized for his pioneering role in deducing the mechanisms behind autophagy – the way in which living cells scavenge and repurpose their own components.



The research, which Dr. Ohsumi conducted in yeast cells, has since turned out to have broad application to human disease, all of which has made autophagy “one of the most intensely studied topics in biomedical research,” said Maria Masucci of the Karolinska Institute in Stockholm, which oversees the prestigious award.

Related: Secrets of the cell: Breakthrough discoveries in the inner works of cells are highlighted by the Gairdner International Awards

Related: Three reasons why Canadian scientists probably won't win a Nobel this year

“I am extremely honoured,” Dr. Ohsumi told Kyodo News in Japan upon learning of the award.

Born in Fukuoka in 1945, Dr. Ohsumi studied a range of cellular mechanisms as a graduate student and junior researcher. He first began working with yeast cells in the mid-1970s, during a stint at Rockefeller University in New York. After returning to Japan, he became an associate professor at Tokyo University in 1988, where he started his own small lab and began working on the puzzle that would ultimately lead to his Nobel.

Although autophagy was first identified in the 1960s, the precise mechanisms behind it were not well understood until Dr. Ohsumi began investigating the process, which cells employ as a way to generate fuel and redirect activity when nutrients are scarce.

In its most common form, autophagy operates like a cellular recycling bin. Responding to environmental signals, the cell first creates a double membrane structure called an autophagosome that surrounds the material targeted for recycling. The autophagosome later merges with another unit known as the lysosome, which contains enzymes that can break down the targeted material. The process allows the cell to clear out its own worn-out parts or those of invaders such as viruses, and turn the byproducts into fuel or into raw materials for building new structures.

Using optical and electron microscopes, Dr. Ohsumi made a detailed study of the autophagy in cells of baker’s yeast. The turning point came when he cultured mutated yeast cells in which one of the genes that is central to the process was silenced. When depleted of nutrients, the mutated cells formed autophagosomes in abundance but were unable to complete the process. The work was described in a landmark paper published in 1992.

More recently, it’s become clear that disruptions to the elegant recycling system, which is regulated by several key genes in the cell’s DNA, are linked to a wide range of maladies, including Parkinson’s disease, Type 2 diabetes and cancer.

Prior to Monday’s announcement, Dr. Ohsumi’s work had been steadily gaining recognition. In 2015, he was named a winner of the Canada Gairdner International Award, which is often a predictor of future Nobel glory.

Janet Rossant, scientific director of the Gairdner Foundation, called the work a “quiet quest” that was initially unfashionable when Dr. Ohsumi began, but “one which he largely single-handedly turned into one of the key areas of research for understanding disease.”

Dr. Ohsumi is the first scientist in five years who will not have to share his Nobel Prize and the eight million Swedish kronor ($1.2-million) that comes with it. With so many top researchers and major discoveries contending for recognition, it is more common now for the prize to be split among multiple recipients.

Although other scientists have contributed to advances in understanding autophagy and its many links to disease, Dr. Ohsumi’s solo win is an indication of the extent to which his research led the field before it was widely taken up by others.

“He stands out as a pioneer when no one else was interested,” said former Gairdner Foundation president John Dirks, who called Dr. Ohsumi “a humble scientist who worked incrementally on one important topic for 40 years.”

With a report from Reuters

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