Every cell in our body is equipped with a form of housecleaning machinery called autophagy. Autophagy is universally present in all cells from yeast to humans. During nutrient starvation, autophagic processes promote cell survival by degrading superfluous cytoplasmic proteins and organelles. The cytoplasmic cargo is captured by a cup shaped structure (phagophore) which elongates and expands to form vesicles called autophagosomes. These autophagosomes fuse with the lysosomes wherein the lysosomal proteases degrade the cargo into basic building blocks which are recycled.
As autophagy is not only involved in clearing superfluous and unwanted cellular components, it is also known to degrade several intracellular pathogens including bacteria (Salmonella, Shigella, Mycobacterium, Group A Streptococcus etc.) and viruses (herpes simplex virus, HIV, etc.). Autophagy also serves a neuroprotective role, as it clears large aggregates of mutant polyubiquitylated proteins resistant to proteasomal degradation. Furthermore, apart from neurodegenerative and infectious diseases, autophagy has been shown to be involved in heart diseases, atherosclerosis, certain myopathies, innate and adaptive immune responses, Crohn's disease and cancer.
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