The importance of recycling…at the cellular level

Yoshinori Osumi. Nobel Laureate in Physiology or Medicine 2016. Credit: 大臣官房人事課
Yoshinori Osumi. Nobel Laureate in Physiology or Medicine 2016. Credit: 大臣官房人事課

Once again, the scientific world has been stirred by the release of the name of this year’s Physiology and Medicine Nobel Award winner, which in this case has gone to the hands of a japanese researcher named Yoshinori Ohsumi, responsible for the discovery of something called the cell autophagy mechanism, which although probably unknown to most, might be one of the reasons humans are so resilient to periods of famine or scarceness of food (starvation).  This cellular mechanism was discovered in yeast, a small eukaryotic single cell system that has been very useful to study cell behaviour and genetics, and a good model for extrapolation for humans, since we are also eucariotic organisms (eukaryotes differ from bacteria in that their genetic material is isolated from the rest of the cellular components by a nuclear membrane).

Why is a subcellular cleaning/recycling mechanism so important? more especifically, why is it important for us, humans?

Autophagy is defined as a process by which cells encapsulate large dysfunctional proteins, aging organelles, and invading pathogens in vesicles and then send them to the lysosome for degradation, helping keep the cell “healthy” and functional. However, when there are issues in the functioning in the system, cell malfunction and therefore disease, are bound to appear. For instance, it has been described that several mutated genes found in neurodegenerative diseases are implicated in the autophagy system (not surprisingly, since some of these are considered proteinopathies, characterized by the accumulation of misfolded proteins, that the cell is incapable to clear of).

Autophagy deregulation and disease in Parkinson's. Credit: Cheung and Ip, Molecular Brain, 2009
Autophagy deregulation and disease in Parkinson’s. Credit: Cheung and Ip, Molecular Brain, 2009

As well as responsible for aging diseases, when under system-malfunction, it also offers a window for opportunity, since an increased functionality of the cellular clearing pathways would definitely increase healthspan, and help the fight against aging diseases, so closely related to a worsening of cellular metabolism. Moreover, there could be a link between strategies directed towards extended life span via caloric restriction and improved autophagy mechanisms, since a lack of external energetic resources would maybe promote the reutilization and recycling of subcellular components and faster turnover of defective subcellular building blocks.

On a day like today, when everyone suddenly realises the importance of working in the trash managing system of cells, is when we have to thank Yoshinosi Ohsumi that he followed his heart and did not just simply follow the latest research fashion of his day. Because, even if as he says, he is just a basic researcher in yeast, this great humble scientist took us one step further towards understanding and (hopefully) curing some aging-related diseases, like Alzheimer’s.