What is autophagy? Why is it useful? Why is it in news now?
The word autophagy originates from two Greek words meaning “self-eating”. It refers to the process in which cellular junk is captured and sealed in sack-like membranes, called autophagosomes. The sealed contents are transported to another structure called the lysosome. Autophagy allows the orderly degradation and recycling of cellular components. The process is crucial for preventing cancerous growths, warding off infection and, by maintaining a healthy metabolism, it helps protect against conditions like diabetes. The contents are degraded and recycled. In the context of disease, autophagy has been seen as an adaptive response to stress. In the extreme case of starvation, the breakdown of cellular components promotes cellular survival by maintaining cellular energy levels. Contemporary autophagy research began in 1990s with the identification of autophagy-related genes by yeast researchers. One of them, Japanese scientist Yoshinori Ohsumi, received the 2016 Nobel Prize in Physiology or Medicine for discoveries on how cells break down and recycle their own components. By studying the process in yeast cells, Ohsumi identified the main genes involved in autophagy and showed how the proteins they code for come together to build the autophagosome membrane. He later showed that a similar cellular recycling process occurs in human cells - and that our cells would not survive without it.