ALG2/YGL065C Summary Help

Standard Name ALG2 1
Systematic Name YGL065C
Feature Type ORF, Verified
Description Mannosyltransferase in the N-linked glycosylation pathway; catalyzes two consecutive steps in the N-linked glycosylation pathway; alg2 mutants exhibit temperature-sensitive growth and abnormal accumulation of the lipid-linked oligosaccharide Man2GlcNAc2-PP-Dol (1, 2, 3, 4 and see Summary Paragraph)
Name Description Asparagine-Linked Glycosylation 5
Chromosomal Location
ChrVII:381271 to 379760 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All ALG2 GO evidence and references
  View Computational GO annotations for ALG2
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 2 genes
Classical genetics
Large-scale survey
reduction of function
9 total interaction(s) for 8 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 3
  • Affinity Capture-Western: 1
  • Two-hybrid: 1

Genetic Interactions
  • Dosage Rescue: 1
  • Negative Genetic: 1
  • Synthetic Growth Defect: 1
  • Synthetic Lethality: 1

Expression Summary
Length (a.a.) 503
Molecular Weight (Da) 58,047
Isoelectric Point (pI) 6.22
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrVII:381271 to 379760 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2011-02-03 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1512 381271..379760 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 SGDIDS000003033

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 6, 3).

Alg2p is a mannosyltransferase that catalyzes the addition of both the second and third mannose moieties to the growing oligosaccharide chain during lipid-linked oligosaccharide (LLO) biosynthesis. The second mannose is added via an alpha-1,3 linkage, while the third mannose is added via an alpha-1,6 linkage (4). Yeast alg2 mutants exhibit temperature-sensitive growth and accumulate oligosaccharide chains with one or two mannose residues (1). Alg2p and Alg11p each form independent complexes with Alg1p, but not with each other, on the cytosolic side of the endoplasmic reticulum (7).

The human homolog, hALG2 (OMIM), is an alpha 1,3 mannosyltransferase that adds the second mannose to the chain (Alg1p adds the first mannose) and is capable of complementing the yeast alg2-1 mutation (8). Human ALG2 is mutated in the congenital disorder of glycosylation CDG-Ii (OMIM). Note: there is an unrelated human gene also known as ALG2, for apoptosis-linked gene 2 (OMIM). The Rhizomucor pusillus ALG2 homolog also complements alg2-1 and has been identified as either an alpha 1,3 or alpha 1,6 mannosyltransferase (9).

Last updated: 2005-07-12 Contact SGD

References cited on this page View Complete Literature Guide for ALG2
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) Jackson BJ, et al.  (1993) Biosynthesis of asparagine-linked oligosaccharides in Saccharomyces cerevisiae: the alg2 mutation. Glycobiology 3(4):357-64
3) Burda P and Aebi M  (1999) The dolichol pathway of N-linked glycosylation. Biochim Biophys Acta 1426(2):239-57
4) O'reilly MK, et al.  (2006) In vitro evidence for the dual function of Alg2 and Alg11: essential mannosyltransferases in N-linked glycoprotein biosynthesis. Biochemistry 45(31):9593-603
5) Huffaker TC and Robbins PW  (1982) Temperature-sensitive yeast mutants deficient in asparagine-linked glycosylation. J Biol Chem 257(6):3203-10
6) Herscovics A and Orlean P  (1993) Glycoprotein biosynthesis in yeast. FASEB J 7(6):540-50
7) Gao XD, et al.  (2004) Physical interactions between the Alg1, Alg2, and Alg11 mannosyltransferases of the endoplasmic reticulum. Glycobiology 14(6):559-70
8) Thiel C, et al.  (2003) A new type of congenital disorders of glycosylation (CDG-Ii) provides new insights into the early steps of dolichol-linked oligosaccharide biosynthesis. J Biol Chem 278(25):22498-505
9) Takeuchi K, et al.  (1999) Characterization of an alg2 mutant of the zygomycete fungus Rhizomucor pusillus. Glycobiology 9(12):1287-93