Jawaharlal Nehru Centre for Advanced Scientific Research - An Autonomous Institution

Autophagy

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, where lysosomal proteases degrade the cargo into basic building blocks that are then recycled.

Autophagy is not only involved in clearing superfluous and unwanted cellular components, but is also known to degrade several intracellular pathogens, including bacteria (Salmonella, Shigella, Mycobacterium, Group A Streptococcus) and viruses (herpes simplex virus, HIV, etc.).

Autophagy also serves a neuroprotective role, clearing large aggregates of mutant polyubiquitylated proteins that are resistant to proteasomal degradation.

Furthermore, beyond neurodegenerative and infectious diseases, autophagy has been shown to play roles in heart diseases, atherosclerosis, certain myopathies, immune responses (both innate and adaptive), Crohn's disease, and cancer.