ALG12
Function
Mannosyltransferase that operates in the biosynthetic pathway of dolichol-linked oligosaccharides, the glycan precursors employed in protein asparagine (N)-glycosylation. The assembly of dolichol-linked oligosaccharides begins on the cytosolic side of the endoplasmic reticulum membrane and finishes in its lumen. The sequential addition of sugars to dolichol pyrophosphate produces dolichol-linked oligosaccharides containing fourteen sugars, including two GlcNAcs, nine mannoses and three glucoses. Once assembled, the oligosaccharide is transferred from the lipid to nascent proteins by oligosaccharyltransferases. In the lumen of the endoplasmic reticulum, adds the eighth mannose residue in an alpha-1,6 linkage onto Man(7)GlcNAc(2)-PP-dolichol to produce Man(8)GlcNAc(2)-PP-dolichol.
Involvement in disease
Congenital disorder of glycosylation 1G
CDG1G
A form of congenital disorder of glycosylation, a multisystem disorder caused by a defect in glycoprotein biosynthesis and characterized by under-glycosylated serum glycoproteins. Congenital disorders of glycosylation result in a wide variety of clinical features, such as defects in the nervous system development, psychomotor retardation, dysmorphic features, hypotonia, coagulation disorders, and immunodeficiency. The broad spectrum of features reflects the critical role of N-glycoproteins during embryonic development, differentiation, and maintenance of cell functions.
None
The disease is caused by variants affecting the gene represented in this entry.
Pathway
Protein modification; protein glycosylation.
Sequence Similarities
Belongs to the glycosyltransferase 22 family.
Cellular localization
- Endoplasmic reticulum membrane
- Multi-pass membrane protein
Alternative names
PP14673, ALG12, Asparagine-linked glycosylation protein 12 homolog, Mannosyltransferase ALG12 homolog, Membrane protein SB87, hALG12