Nobel prize winner in physiology demonstrates importance of autophagy

Alex Haber
Staff Writer

The 2016 Nobel prize in physiology was awarded to Japanese cell biologist Yoshinori Ohsumi, Ph.D., for his work in the field of autophagy, the process by which cells recycle their material.

Autophagy is a Greek term which means “self-eating.” The process, crucial to life, involves the breakdown of proteins and nonessential cell components. The process involves the movement of cytoplasmic materials in vesicles to the lysosome. A lysosome is a membrane bound organelle. It contains a variety of hydrolytic enzymes that can breakdown the contents of the autophagosome, the vesicle containing the materials designated for destruction. The materials that were degraded are then made available for reuse. The process is vital for proper cellular function.

Ohsumi was born in Fukouka, Japan, and received his Ph.D. in the University of Tokyo in 1974. Initially Ohsumi began his work in chemistry, but decided to leave the field due to the lack of opportunities in the field. Eventually he decided on the field of molecular biology, but could not initially attain a job in the field. He eventually accepted a position as a junior professor at the University of Tokyo. Here, he switched from studying genetics to cell biology. Ohsumi is now a professor at the Tokyo Institute of Technology.

The work that specifically won him this prestigious award was done on protein degradation in the vacuole. The vacuole, found in plant cells corresponds to the lysosome in animal cells. His work focused on the degradation system in yeast cells. His work proved that autophagy occurred in yeast cells, and worked to identify the first genes associated with enzymes required for autophagy.

Ohsumi did not discover the process of autophagy, but rather he made clear its importance in the function of the cell. In order to prove this, he blocked the process and observed the accumulation of vesicles in the yeast cell. This did two things. One, it proved that autophagy occurs in yeast. In addition, it also demonstrated the necessity of the process to life. This he found through his observation of the effects on the cell from inhibiting autophagy.

Beyond characterizing the importance of the process, Ohsumi also identified 15 genes that are necessary for the process. While since then, other genes have been identified, it was his work that helped to spark the theory that these proteins may be good therapeutic targets for a variety of diseases.

The field has expanded in various directions since Ohsumi characterized the process of autophagy and identified the genes responsible. Much of the research now is done to elicit its role in neurodegenerative disorders and even cancer. Dysfunctions in the process of autophagy has been indicated in a variety of diseases, such as Parkinson’s disease and cancer. In both cases, the cell loses control of its ‘recycling process.’ This leads to the accumulation of vesicles within the cell. These vesicles then can inhibit cellular activities by a variety of means.

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