In yeast this activity is catalysed by a dedicated enzyme that processes unfolded protein-bound Man8GlcNAc2 N-glycans within the endoplasmic reticulum to Man7GlcNAc2. The exposed alpha-1,6-linked mannose residue in the product enables the recognition by the YOS9 lectin, targeting the proteins for degradation. In mammalian cells this activity is part of the regular processing of N-glycosylated proteins, and is not associated with protein degradation. It is carried out by EC 3.2.1.113, Golgi mannosyl-oligosaccharide 1,2-alpha-mannosidase. The names of the isomers listed here are based on a nomenclature system proposed by Prien et al [5].
Nakatsukasa K, Nishikawa S, Hosokawa N, Nagata K, Endo T
Title
Mnl1p, an alpha -mannosidase-like protein in yeast Saccharomyces cerevisiae, is required for endoplasmic reticulum-associated degradation of glycoproteins.
