lipophagy

Definition

Target type: biologicalprocess

The selective degradation of lipid droplets by macroautophagy. [GOC:autophagy, PMID:23708524, PMID:26076903]

Lipophagy is a cellular process that selectively degrades lipid droplets (LDs), specialized organelles that store neutral lipids such as triglycerides and cholesterol esters. It is an essential pathway for maintaining lipid homeostasis, regulating cellular energy production, and eliminating damaged or excess lipids.

Lipophagy is initiated by the formation of a double-membrane structure called a phagophore, which engulfs the LD. The phagophore then matures into an autophagosome, a double-membrane vesicle that encloses the LD. The autophagosome subsequently fuses with a lysosome, a cellular organelle containing hydrolytic enzymes. Within the lysosome, the LD is broken down into its constituent fatty acids and glycerol, which can be used as energy sources or recycled for the synthesis of new lipids.

The process of lipophagy is tightly regulated by a variety of signaling pathways, including the mTOR pathway, which is a master regulator of cell growth and metabolism. When cells are starved for nutrients, the mTOR pathway is inhibited, leading to the activation of autophagy, including lipophagy.

Lipophagy plays a crucial role in various physiological processes, including:

* **Energy production:** By degrading LDs, lipophagy provides cells with a source of energy during periods of starvation or stress.
* **Lipid homeostasis:** Lipophagy helps to maintain a balance between lipid synthesis and degradation, preventing the accumulation of excess lipids in cells.
* **Elimination of damaged lipids:** Damaged or oxidized lipids can be harmful to cells. Lipophagy removes these lipids by degrading them in lysosomes.
* **Cellular differentiation and development:** Lipophagy is involved in the differentiation of certain cell types, such as adipocytes (fat cells), and is important for embryonic development.

Defects in lipophagy have been implicated in a number of diseases, including obesity, fatty liver disease, and neurodegenerative disorders. Understanding the molecular mechanisms of lipophagy is crucial for developing therapies for these conditions.'
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Proteins (1)

Compounds (3)