autophagy

noun

au·​toph·​a·​gy ȯ-ˈtä-fə-jē 

: the biological process that involves the enzymatic breakdown of a cell's cytoplasm or cytoplasmic components (such as damaged or unneeded organelles or proteins) within the lysosomes of the same cell

Most of the time, cells sweep away this debris. They even recycle it for fuel. Through the process of autophagy, or "self-eating," cells create specialized membranes that engulf junk in the cytoplasm and carry it to a region of the cell called the lysosome, where the waste is broken down and burned for energy.

—Gretchen Reynolds

Certain environmental cues (such as starvation, high temperature, low oxygen, hormonal stimulation) or intracellular stress (damaged organelles, accumulation of mutant proteins, microbial invasion) activate signalling pathways that increase autophagy.

—Beth Levine

… proliferating [cancer] cells maintain a nutrient supply by hijacking a natural cell-housekeeping process called autophagy, in which cells chop up and dispose of damaged or obsolete cell components such as proteins.

—Nathan Seppa

Examples of autophagy in a Sentence

Recent Examples on the Web

However, research also suggests that at 18 hours other benefits occur (including positive effects on human growth hormone production, the immune system, and autophagy, which replaces older and less functional body cells). —Bryant Stamford, The Courier-Journal, 8 Aug. 2024

Two modules were especially likely to be disrupted in patients with Alzheimer’s: One included proteins involved in degrading and reprocessing proteins and organelles through processes like autophagy and ubiquitination, while the other was involved in glycolysis, the processing of sugars. —Rohan Rajeev, STAT, 28 June 2024

The proteins encoded bring together three important functions of the cell: autophagy, immunity and mitochondrial function. —Matthew Farrer, Discover Magazine, 13 Apr. 2024

All of this is done to have her body in a state of autophagy, which is the way our body moves out unnecessary and dysfunctional cellular components. —Victoria Uwumarogie, Essence, 3 Oct. 2023

To date, most studies on fasting and autophagy have been performed on animals and suggest that autophagy begins after about 24 hours of fasting. —Bryant Stamford, The Courier-Journal, 29 June 2023

Fast Lean Pro is a weight loss supplement that works by accelerating the process of autophagy in the body. —Amber Smith, Discover Magazine, 25 May 2023

Augmenting autophagy in older individuals with amyloidosis, Kelly hopes, will allow their aged immune cells to take out the trash properly. —Amber Dance, Discover Magazine, 13 Apr. 2023

How long to fast for autophagy to begin is up for debate. —Erica Sweeney, Men's Health, 31 Mar. 2023

Word History

Etymology

borrowed from French autophagie, from auto- auto- + -phagie -phagy

Note: As a term in cell biology introduced by the Belgian immunologist Jules Bordet (1870-1961) in "La bactériophagie ou l'autolyse microbienne transmissible," Volume jubilaire publié à l'occasion du centenaire de la Société royale des sciences médicales et naturelles de Bruxelles (Brussels, 1922), p. 363.

First Known Use

1924, in the meaning defined above

Medical Definition

autophagy

noun

au·​toph·​a·​gy ȯ-ˈtäf-ə-jē 

plural autophagies

: digestion of cellular constituents by enzymes of the same cell

autophagic

-jik 

adjective