The name DIE2, for Derepression of ITR1 Expression, comes from a screen for genes involved in regulation of an inositol transporter gene (1). The name ALG10 was assigned after it was determined that the gene plays a role in asparagine-linked glycosylation (4).

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).

Die2p is an alpha-1,2 glucosyltransferase that catalyzes the addition of the third glucose moiety during lipid-linked oligosaccharide (LLO) assembly (2) in the lumen of the endoplasmic reticulum. This is the final sugar added to an LLO before it is transferred as a whole to asparagine; Alg8p adds the second glucose. The human (OMIM) and rat homologs of DIE2 are called KCR1, for potassium channel regulator.

Last updated: 2005-07-01