MAN1B1,EDEM2 hydrolyse 1,2-linked mannose (b branch)

Stable Identifier
Reaction [transition]
Homo sapiens
Trimming of the terminal mannose on the B branch
Locations in the PathwayBrowser
SVG |   | PPTX  | SBGN
Click the image above or here to open this reaction in the Pathway Browser
The layout of this reaction may differ from that in the pathway view due to the constraints in pathway layout

The enzyme ER Man I can slowly trim up to four of the mannoses on the N-glycan on unfolded proteins accumulated in the ER. This step describes the removal of the mannose in the B position (Gonzalez et al. 1999, Karaveg et al. 2005, Avezov et al. 2008). The ER degradation-enhancing alpha-mannosidase-like protein 2 (EDEM2) is also able to hydrolyse the alpha-1,2-mannose from (GlcNAc)2 (Man)9 to form (GlcNAc)2 (Man)8b (Ninagawa et al. 2014).

Literature References
PubMed ID Title Journal Year
18003979 Endoplasmic reticulum (ER) mannosidase I is compartmentalized and required for N-glycan trimming to Man5-6GlcNAc2 in glycoprotein ER-associated degradation

Herscovics, A, Ehrlich, M, Lederkremer, GZ, Avezov, E, Frenkel, Z

Mol Biol Cell 2008
10409699 Identification, expression, and characterization of a cDNA encoding human endoplasmic reticulum mannosidase I, the enzyme that catalyzes the first mannose trimming step in mammalian Asn-linked oligosaccharide biosynthesis

Karaveg, K, Gonzalez, DS, Moremen, KW, Lal, A, Vandersall-Nairn, AS

J Biol Chem 1999
15713668 Mechanism of class 1 (glycosylhydrolase family 47) {alpha}-mannosidases involved in N-glycan processing and endoplasmic reticulum quality control

Liu, ZJ, Karaveg, K, Moremen, KW, Glushka, J, Tempel, W, Wang, BC, Siriwardena, A

J. Biol. Chem. 2005
25092655 EDEM2 initiates mammalian glycoprotein ERAD by catalyzing the first mannose trimming step

Kamiya, Y, Takeda, S, Ishikawa, T, Sakuma, T, Sumitomo, Y, Okada, T, Yamamoto, T, Horimoto, S, Mori, K, Ninagawa, S, Kato, K

J. Cell Biol. 2014
Event Information
Catalyst Activity

mannosyl-oligosaccharide 1,2-alpha-mannosidase activity of MAN1B1,EDEM2 [endoplasmic reticulum quality control compartment]

Cite Us!