Nobel Prize Medicine: Cell recycling research by Ohsumi
Experiments identifying genes for autophagy (cell recycling) wins Ohsumi of Japan Nobel Prize in medicine.
Experiments identifying genes for autophagy (cell recycling) wins Ohsumi of Japan Nobel Prize in medicine.
NOBEL PRIZE & MEDICINE
Japan's Ohsumi wins Nobel Prize for work on cell 'recycling'
3/10/2016
AFP News agency
Yoshinori Ohsumi of Japan on Monday won the Nobel Prize in Medicine for his work in the field of cell biology on autophagy -- a process whereby cells "eat themselves".
Autophagy is defined as the process of orderly disassembling and recycling of the parts of old cells or cell recycling process (see here & here).
Disruption of this process can cause diseases such as Parkinson's disease and diabetes.
Figure 1: Our cells have different specialized compartments. Lysosomes constitute one such compartment and contain enzymes for digestion of cellular contents. A new type of vesicle called autophagosome was observed within the cell. As the autophagosome forms, it engulfs cellular contents, such as damaged proteins and organelles. Finally, it fuses with the lysosome, where the contents are degraded into smaller constituents. This process provides the cell with nutrients and building blocks for renewal (Source: Nobel.org)
Autophagy is a fundamental process in cell physiology with major implications for human health and disease.
The process of autophagy is essential for the orderly degradation and recycling of damaged cell parts.
The failure of autophagy is believed to be responsible for ageing and cell damage.
Figure 2: In yeast (left panel) a large compartment called the vacuole corresponds to the lysosome in mammalian cells. Ohsumi generated yeast lacking vacuolar degradation enzymes. When these yeast cells were starved, autophagosomes rapidly accumulated in the vacuole (middle panel). His experiment demonstrated that autophagy exists in yeast. As a next step, Ohsumi studied thousands of yeast mutants (right panel) and identified 15 genes that are essential for autophagy. (Source: Nobel.org)
Last year, Irish-born William Campbell of the US, Satoshi Omura of Japan and China's Tu Youyou won the prestigious award for their discoveries of treatments against parasites (see here).
BRILLIANT EXPERIMENTS OPENED NEW FIELD FOR STUDY
Researchers first observed during the 1960s that the cell could destroy its own contents by wrapping them up in membranes and transporting them to a recycling compartment called the lysosome.
"Difficulties in studying the phenomenon meant that little was known until, in a series of brilliant experiments in the early 1990s, Yoshinori Ohsumi used baker's yeast to identify genes essential for autophagy."
He then went on to explain the underlying mechanisms for autophagy in yeast and showed that similar sophisticated machinery is used in human cells.
Ohsumi's discoveries "have led to a new paradigm in the understanding of how the cell recycles its contents," the jury said.
"Mutations in autophagy genes can cause disease, and the autophagic process is involved in several conditions including cancer and neurological disease," it added.
Figure 3: Ohsumi studied the function of the proteins encoded by key autophagy genes. He delineated how stress signals initiate autophagy and the mechanism by which proteins and protein complexes promote distinct stages of autophagosome formation.
Ohsumi, 71, received a PhD from the University of Tokyo in 1974. He is currently a professor at the Tokyo Institute of Technology.
The prize comes with eight million Swedish kronor (around $936,000 or 834,000 euros).
http://www.bangkokpost.com/news/asia/1101493/japans-ohsumi-wins-nobel-prize-for-work-on-cell-recycling
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