This eukaryotic enzyme performs the final step in the synthesis of the lipid-linked oligosaccharide, attaching D-glucose in an alpha-1,2-linkage to the outermost D-glucose in the long branch. The lipid-linked oligosaccharide is involved in N-linked protein glycosylation of selected asparagine residues of nascent polypeptide chains in eukaryotic cells.
This eukaryotic enzyme performs the final step in the synthesis of the lipid-linked oligosaccharide, attaching D-glucose in an alpha-1,2-linkage to the outermost D-glucose in the long branch. The lipid-linked oligosaccharide is involved in N-linked protein glycosylation of selected asparagine residues of nascent polypeptide chains in eukaryotic cells.
lipid-linked Glc1Man9GlcNAc2 oligosaccharide is not a substrate for the ALG10 transferase. Alg10p is a highly specific alpha-1,2 glucosyltransferase. alg10 mutant strains accumulate lipid-linked Glc2Man9GlcNAc2. Hypoglycosylation of secreted proteins in alg10 deletion strains demonstrates that the terminal alpha-1,2-linked glucose residue is a key element in substrate recognition by the oligosaccharyltransferase. This ensures that primarily completely assembled oligosaccharide is transferred to protein
lipid-linked Glc1Man9GlcNAc2 oligosaccharide is not a substrate for the ALG10 transferase. Alg10p is a highly specific alpha-1,2 glucosyltransferase. alg10 mutant strains accumulate lipid-linked Glc2Man9GlcNAc2. Hypoglycosylation of secreted proteins in alg10 deletion strains demonstrates that the terminal alpha-1,2-linked glucose residue is a key element in substrate recognition by the oligosaccharyltransferase. This ensures that primarily completely assembled oligosaccharide is transferred to protein
compared to most GT-C superfamily enzymes, ALG10 shows two additional central membrane segments, resulting in a 1-8-4 organization with the N-terminus oriented toward the cytoplasmic face of the ER membrane and the C-terminus facing the lumen. The conserved patterns in ALG10 align with STT3 and DPY19
alg10 mutant strains accumulate lipid-linked Glc2Man9GlcNAc2. Hypoglycosylation of secreted proteins in alg10 deletion strains demonstrates that the terminal alpha-1,2-linked glucose residue is a key element in substrate recognition by the oligosaccharyltransferase. This ensures that primarily completely assembled oligosaccharide is transferred to protein
alg10 mutant strains accumulate lipid-linked Glc2Man9GlcNAc2. Hypoglycosylation of secreted proteins in alg10 deletion strains demonstrates that the terminal alpha-1,2-linked glucose residue is a key element in substrate recognition by the oligosaccharyltransferase. This ensures that primarily completely assembled oligosaccharide is transferred to protein. The terminal alpha-1,2 glucose residue on the lipid-bound oligosaccharide serves as a signal to indicate complete assembly of the core oligosaccharide. Once transferred to protein, the removal of this signal by glucosidase I might ensure that glycosylation sites remain glycosylated and are not deglycosylated by the oligosaccharyltransferase complex
a homozygous Arabidopsis T-DNA insertion mutant accumulates mainly lipid-linked Glc2Man9Glc-NAc2 and displays a severe protein underglycosylation defect. Mutant plants have altered leaf size when grown in soil. The inactivation of the enzyme gene in Arabidopsis results in the activation of the unfolded protein response, increased salt sensitivity and suppression of the phenotype of alpha-glucosidase I-deficient plants
Alg10 gene deletion mutants, as well as endoplasmic reticulum lumenal mannosyltransferases (Alg3, Alg9, and Alg12), glucosyltransferases (Alg6, Alg8), or oligosaccharyltransferase subunits (Ost3, Ost5, and Ost6) deletion mutants, show decreased glycan occupancy and altered cell wall proteomes. Mutations in earlier mannosyltransferase or glucosyltransferase steps of glycan biosynthesis have stronger hypoglycosylation phenotypes, but glucosyltransferase defects are more severe
The ALG10 locus of Saccharomyces cerevisiae encodes the alpha-1,2 glucosyltransferase of the endoplasmic reticulum: the terminal glucose of the lipid-linked oligosaccharide is required for efficient N-linked glycosylation
BRENDA home
History
Enzyme Nomenclature
2.4.1.256 dolichyl-P-Glc:Glc2Man9GlcNAc2-PP-dolichol alpha-1,2-glucosyltransferase
top
