glycophagy

Definition

Target type: biologicalprocess

The selective degradation of glycogen by macroautophagy. [GOC:autophagy, PMID:21893048]

Glycophagy is a specialized form of autophagy, a cellular process responsible for the breakdown and recycling of cellular components, that specifically targets and degrades glycans (complex carbohydrates) and glycoconjugates (molecules containing glycans). This process plays a crucial role in maintaining cellular homeostasis, regulating various cellular processes, and responding to stress conditions.

Here's a detailed breakdown of glycophagy:

1. **Initiation:** Glycophagy is triggered by various stimuli, including nutrient deprivation, cellular stress, and changes in the cellular environment. These stimuli activate signaling pathways that lead to the formation of autophagosomes, double-membrane vesicles responsible for encapsulating cellular cargo for degradation.

2. **Cargo Recognition and Selection:** Glycans and glycoconjugates are recognized by specific adaptor proteins and receptors, such as Galectin-8, N-acetylglucosamine (GlcNAc) receptor, and other glycosylases. These adaptors bind to glycans on target molecules, marking them for degradation by autophagy.

3. **Autophagosome Formation:** The adaptor proteins recruit components of the autophagy machinery, including Atg proteins. These proteins orchestrate the formation of autophagosomes, which engulf the glycan-containing cargo.

4. **Fusion with Lysosomes:** Autophagosomes subsequently fuse with lysosomes, which are acidic organelles containing hydrolytic enzymes. This fusion creates a hybrid structure called an autolysosome.

5. **Glycan Degradation:** Within the autolysosome, the lysosomal enzymes break down the captured glycans and glycoconjugates into simpler sugars and other breakdown products.

6. **Recycling and Reuse:** The products of glycan degradation are recycled back into the cell, providing essential building blocks for biosynthesis and energy production.

Glycophagy plays vital roles in cellular function, including:

* **Cellular Homeostasis:** By degrading damaged or misfolded glycoproteins and other glycan-containing structures, glycophagy maintains cellular integrity and prevents the accumulation of potentially harmful molecules.
* **Metabolic Regulation:** Glycophagy contributes to the regulation of cellular metabolism by controlling the levels of specific carbohydrates and glycoconjugates.
* **Stress Response:** Glycophagy is activated during periods of stress, such as nutrient deprivation, to ensure survival by mobilizing stored carbohydrates and providing energy.
* **Immune Function:** Glycophagy plays a role in immune response by modulating the presentation of glycan antigens on the cell surface, potentially influencing immune cell activation.

Disruptions in glycophagy are linked to various diseases, including cancer, neurodegenerative disorders, and metabolic diseases. Further research is ongoing to elucidate the intricate mechanisms of glycophagy and its role in health and disease.'
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Proteins (2)

Compounds (41)