2016 Nobel Medicine Prize Awarded to Yoshinori Ohsumi for Autophagy Research

The Nobel Prize in Physiology or Medicine is awarded annually by the Nobel Foundation for outstanding discoveries. Under Alfred Nobel’s 1895 will, it is one of five prizes, alongside chemistry, physics, literature and peace, awarded since 1901. Each laureate receives a medal, diploma and varying monetary award on 10 December, Nobel’s death anniversary.

The 2016 prize went to Japanese scientist Yoshinori Ohsumi for discovering and elucidating mechanisms of autophagy, a fundamental process degrading and recycling cellular components.

Autophagy (autophagocytosis) combines Greek autóphagos, “self-eating,” and kýtos, “hollow.” Emerging in the 60s, researchers observed cells forming sack-like lysosomes and transporting their contents to recycling compartments for breakdown.

Little was understood until the early 90s, when Ohsumi used ingenious baker’s yeast experiments to identify essential genes. He later clarified yeast mechanisms and showed similar machinery operates in human cells.

His discoveries transformed understanding of cellular recycling, revealing autophagy’s importance in starvation adaptation and infection responses. Mutations in its genes cause cancer and neurological and other autophagy-related diseases.

“Degradation” – A Central Function in All Living Cells

In the mid-1950s, scientists identified a cellular compartment containing carbohydrate-, protein- and fat-digesting enzymes. The lysosome functions as a degradation station. By the 1960s, large quantities of components and sometimes entire specialized compartments were observed inside it.

Cells evidently had a large-cargo transport system. Extensive biochemical and microscopic work identified a vesicle carrying cellular cargo to lysosomes for degradation: the autophagosome.

Research in 1970 and 1980 focused on another damaged-protein degradation system, the proteasome . Its discoverers received the 2004 Nobel Chemistry Prize. It degrades proteins individually but did not explain disposal of large complexes and worn organelles; autophagy provides that explanation.

The Breakthrough Experiment

After working in various fields, Ohsumi began his own laboratory in 1988 and focused on the yeast protein-degrading compartment corresponding to human lysosomes. Yeast was relatively easy to study and useful for modeling human cells and identifying genes in complex processes. Yet its small size made internal structures hard to distinguish; he was unsure autophagy even existed. He reasoned that interrupting degradation while autophagy remained active would accumulate visible autophagosomes. Chemical exposure produced genetically disrupted yeast lacking degradation enzymes, while starvation stimulated autophagy. Within hours, compartments filled with undegraded vesicles—autophagosomes—proving yeast autophagy. More importantly, he established a method for identifying key genes and published the breakthrough in 1992.

Autophagy – A Fundamental Cellular Mechanism

After identifying yeast mechanisms, researchers asked whether other organisms had equivalent control. Nearly identical mechanisms were soon found in human cells.

Ohsumi revealed its vital role in breakdown and recycling. Autophagy rapidly supplies building blocks and energy for renewal, responding to starvation and other stimuli. After infection, it destroys intracellular bacteria and viruses. It contributes to embryonic development and differentiation, while removing damaged proteins and organelles to counter aging’s adverse consequences.

Disrupted autophagy is associated with Parkinson’s disease, type 2 Diabetes and other later-life conditions. Gene defects can cause genetic diseases and are also linked to cancer. Developing medicines targeting autophagy in various diseases is an intense research field.

Although known for over 50 years, its vital medical importance was established through Ohsumi’s groundbreaking work in the 90s.

Autophagy and Osteoarthritis

Autophagy declines with age, a major osteoarthritis cause. Its role influences disease development. Related proteins decline in human and mouse cartilage with age and after injury, indicating joint protection.

Autophagy and Cancer

Autophagy suppresses early cancer by degrading cancer-promoting proteins and cellular elements and removing damaged cells. Later, cancer cells use it to survive treatment-induced metabolic and cellular stress by removing damaged parts. Recent research also identifies it among multidrug-resistance factors.

Autophagy and Parkinson’s Disease

Parkinson’s involves dead brain cells and stem-cell-related nervous tissue abnormalities. Several mutations contribute; lost gene function damages mitochondrial accumulation and protein clustering, causing deterioration. Mitochondria are associated with Parkinson’s. Disease of unknown origin generally involves dysfunctional mitochondria, cellular stress, autophagic changes and protein aggregates.

Another study found that drinking only water for 2-4 days, a prolonged fast , can restart immunity. Periodic fasting stimulates dormant stem cells to become immune cells and clears old/damaged cells. Since starvation activates autophagy, fasting-mimicking calorie restrictionmay reduce cancer, diabetes and cardiovascular risk factors and support healthier living, highlighting autophagy’s role against aging’s adverse effects.