ALG6/YOR002W Summary Help

Standard Name ALG6 1
Systematic Name YOR002W
Feature Type ORF, Verified
Description Alpha 1,3 glucosyltransferase; involved in transfer of oligosaccharides from dolichyl pyrophosphate to asparagine residues of proteins during N-linked protein glycosylation; mutations in human ortholog are associated with disease (2, 3 and see Summary Paragraph)
Name Description Asparagine-Linked Glycosylation 4
Chromosomal Location
ChrXV:329417 to 331051 | ORF Map | GBrowse
Gene Ontology Annotations All ALG6 GO evidence and references
  View Computational GO annotations for ALG6
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 3 genes
Classical genetics
Large-scale survey
336 total interaction(s) for 171 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 2
  • Affinity Capture-RNA: 2
  • Biochemical Activity: 3

Genetic Interactions
  • Negative Genetic: 206
  • Phenotypic Suppression: 59
  • Positive Genetic: 42
  • Synthetic Growth Defect: 15
  • Synthetic Lethality: 7

Expression Summary
Length (a.a.) 544
Molecular Weight (Da) 62,782
Isoelectric Point (pI) 9.87
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrXV:329417 to 331051 | ORF Map | GBrowse
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1635 329417..331051 2011-02-03 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000005528

During N-linked glycosylation of proteins, oligosaccharide chains are assembled on the carrier molecule dolichyl pyrophosphate in the following order: 2 molecules of N-acetylglucosamine (GlcNAc), 9 molecules of mannose, and 3 molecules of glucose. These 14-residue oligosaccharide cores are then transferred to asparagine residues on nascent polypeptide chains in the endoplasmic reticulum (ER). As proteins progress through the Golgi apparatus, the oligosaccharide cores are modified by trimming and extension to generate a diverse array of glycosylated proteins (reviewed in 5, 6).

Alg6p, an alpha 1,3 glucosyltransferase, catalyzes the addition of the first glucose to the growing lipid-linked oligosaccharide (LLO) (7) in the lumen of the endoplasmic reticulum. Alg8p (8, 9) and Die2p (10) (also known as Alg10p) add the second and third glucoses, respectively. In a hexokinase/glucokinase-deficient background, alg6 mutants fail to accumulate intracellular glucose, indicating that glucose accumulates by trimming of glucose from LLO's (11).

Human ALG6 (OMIM) rescues defective glycosylation in alg6 mutant yeast (2, 12, 13, 14, 15). Mutation of human ALG6 causes the congenital disorder of glycosylation CDG-Ic (OMIM) (2, 15), and may exacerbate CDG-Ia (OMIM) (14).

Last updated: 2005-07-01 Contact SGD

References cited on this page View Complete Literature Guide for ALG6
1) Huffaker TC and Robbins PW  (1983) Yeast mutants deficient in protein glycosylation. Proc Natl Acad Sci U S A 80(24):7466-70
2) Imbach T, et al.  (1999) A mutation in the human ortholog of the Saccharomyces cerevisiae ALG6 gene causes carbohydrate-deficient glycoprotein syndrome type-Ic. Proc Natl Acad Sci U S A 96(12):6982-7
3) Reiss G, et al.  (1996) Isolation of the ALG6 locus of Saccharomyces cerevisiae required for glucosylation in the N-linked glycosylation pathway. Glycobiology 6(5):493-8
4) Huffaker TC and Robbins PW  (1982) Temperature-sensitive yeast mutants deficient in asparagine-linked glycosylation. J Biol Chem 257(6):3203-10
5) Herscovics A and Orlean P  (1993) Glycoprotein biosynthesis in yeast. FASEB J 7(6):540-50
6) Burda P and Aebi M  (1999) The dolichol pathway of N-linked glycosylation. Biochim Biophys Acta 1426(2):239-57
7) Burda P, et al.  (1999) Ordered assembly of the asymmetrically branched lipid-linked oligosaccharide in the endoplasmic reticulum is ensured by the substrate specificity of the individual glycosyltransferases. Glycobiology 9(6):617-25
8) Stagljar I, et al.  (1994) New phenotype of mutations deficient in glucosylation of the lipid-linked oligosaccharide: cloning of the ALG8 locus. Proc Natl Acad Sci U S A 91(13):5977-81
9) Munoz MD, et al.  (1994) Glycosylation of yeast exoglucanase sequons in alg mutants deficient in the glucosylation steps of the lipid-linked oligosaccharide. Presence of glucotriose unit in Dol-PP-GlcNAc2Man9Glc3 influences both glycosylation efficiency and selection of N-linked sites. Biochim Biophys Acta 1201(3):361-6
10) Burda P and Aebi M  (1998) 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. Glycobiology 8(5):455-62
11) Miseta A, et al.  (2003) A Saccharomyces cerevisiae mutant unable to convert glucose to glucose-6-phosphate accumulates excessive glucose in the endoplasmic reticulum due to core oligosaccharide trimming. Eukaryot Cell 2(3):534-41
12) Imbach T, et al.  (2000) Multi-allelic origin of congenital disorder of glycosylation (CDG)-Ic. Hum Genet 106(5):538-45
13) Westphal V, et al.  (2000) Reduced heparan sulfate accumulation in enterocytes contributes to protein-losing enteropathy in a congenital disorder of glycosylation. Am J Pathol 157(6):1917-25
14) Westphal V, et al.  (2002) A frequent mild mutation in ALG6 may exacerbate the clinical severity of patients with congenital disorder of glycosylation Ia (CDG-Ia) caused by phosphomannomutase deficiency. Hum Mol Genet 11(5):599-604
15) Westphal V, et al.  (2000) Analysis of multiple mutations in the hALG6 gene in a patient with congenital disorder of glycosylation Ic. Mol Genet Metab 70(3):219-23