Asparagine Linked Glycosylation Protein 13 (ALG13)

ALG13 is a subunit of a bipartite UDP-N-acetylglucosamine transferase. It heterodimerizes with asparagine-linked glycosylation 14 homolog to form a functional UDP-GlcNAc glycosyltransferase that catalyzes the second sugar addition of the highly conserved oligosaccharide precursor in endoplasmic reticulum N-linked glycosylation. Multiple transcript variants encoding different isoforms have been found for this gene.The deduced 161-amino acid protein has a calculated molecular mass of 18.2 kD and shares 28% amino acid identity with yeast Alg13. Alg13 contains a predicted catalytic domain but lacks a membrane-spanning domain. Fluorescence microscopy and subcellular fractionation studies localized the S. cerevisiae Alg13 protein to the endoplasmic reticulum membrane.