protein alpha-1,2-demannosylation

Definition

Target type: biologicalprocess

The removal of one or more alpha 1,2-linked mannose residues from a mannosylated protein. [GOC:bf, GOC:PARL, PMID:21062743, PMID:25092655]

Alpha-1,2-demannosylation is a crucial step in the N-glycan processing pathway, where the removal of terminal alpha-1,2-linked mannose residues from N-glycans occurs. This process is catalyzed by a specific family of enzymes called alpha-1,2-mannosidases, which are found in the endoplasmic reticulum (ER) and Golgi apparatus of eukaryotic cells.

The process of alpha-1,2-demannosylation plays a vital role in controlling the fate of newly synthesized glycoproteins in the secretory pathway. It is essential for proper protein folding and quality control. The specific steps involved in this process can be summarized as follows:

1. **Glycosylation:** Newly synthesized proteins in the ER undergo N-glycosylation, where a precursor oligosaccharide containing multiple mannose residues is attached to asparagine residues in the polypeptide chain.

2. **Trimming of the precursor oligosaccharide:** The precursor oligosaccharide undergoes a series of trimming steps by various glycosidases, including alpha-1,2-mannosidases. These enzymes remove terminal alpha-1,2-linked mannose residues from the N-glycan.

3. **Quality control:** The presence or absence of specific mannose residues on the N-glycan serves as a signal for quality control mechanisms. If the protein is properly folded, the mannose residues are trimmed by alpha-1,2-mannosidases, allowing the protein to proceed through the secretory pathway.

4. **Further processing and sorting:** After trimming, the N-glycans can undergo further processing and modification in the Golgi apparatus, depending on the specific protein and its destination. The modified glycans can play roles in protein stability, solubility, trafficking, and recognition by other molecules.

Overall, alpha-1,2-demannosylation is a critical step in the N-glycan processing pathway that ensures proper protein folding, quality control, and subsequent trafficking of glycoproteins. It is a tightly regulated process involving specific enzymes and intricate mechanisms that ensure the proper function and fate of glycoproteins in the secretory pathway.'
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Proteins (1)

Compounds (1)