Autophagy definition

Autophagy (literally “self-eating”) is a lysosome-mediated intracellular bulk degradation pathway employed by eukaryotic cells when subjected to certain hostile conditions (such as nutrient deprivation) that triggers digestion and recycling of cellular contents. Various cytoplasmic constituents, including organelles, aggregated proteins, and long-lived proteins are sequestered into double-membrane autophagosomes, which subsequently fuse with lysosomes where their contents are degraded. Autophagic activity is critical to the maintenance of cellular homeostasis and energy balance. Although typically low under basal conditions, autophagy can be markedly upregulated by a variety of physiological stimuli such as nutrient starvation, hypoxia, endoplasmic reticulum stress, as well as immune and hormonal stimulation. Mounting evidence has connected malfunctions in autophagic processes to many clinically relevant diseases including cancer, neurodegeneration, diabetes, autoimmunity, and cardiovascular disease. Development of autophagy-targeting therapies will depend on a deeper understanding of the benefits, and potential consequences, of altering autophagic activity.