Reaction: Defective ALG8 does not add glucose to the N-glycan precursor
- in pathway: Defective ALG8 causes CDG-1h
The probable dolichyl pyrophosphate Glc1Man9GlcNAc2 alpha-1,3-glucosyltransferase (ALG8) (Chantret et al. 2003) normally adds the second glucose moiety to the lipid-linked oligosaccharide precursor (LLO aka N-glycan precursor) which is required for subsequent N-glycosylation of proteins. Defects in ALG8 can cause congenital disorder of glycosylation 1h (ALG8-CDG, CDG-1h; MIM:608104), a multisystem disorder characterised by under-glycosylated serum glycoproteins (Chantret et al. 2003, Schollen et al. 2004). ALG8 deficiency is accompanied by an accumulation of the N-glycan precursor (Glc)1 (GlcNAc)2 (Man)9 (PP-Dol)1. Mutations that can cause ALG8-CDG include T47P, G275D, V133Sfs*3 and T138Kfs*19 (Chantret et al. 2003, Schollen et al. 2004).
Reaction - small molecule participants:
(Glc)1 (GlcNAc)2 (Man)9 (PP-Dol)1 [integral component of lumenal side of endoplasmic reticulum membrane]
DbGP [integral component of lumenal side of endoplasmic reticulum membrane]
Reactome.org reaction link: R-HSA-4724330
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Reaction input - small molecules:
alpha-Gal-(1->3)-alpha-Glc-(1->3)-alpha-Man-(1->2)-alpha-Man-(1->2)-alpha-Man-(1->3)-[alpha-Man-(1->2)-alpha-Man-(1->3)-[alpha-Man-(1->2)-alpha-Man-(1->6)]-alpha-Man-(1->6)]-beta-Man-(1->4)-beta-GlcNAc-(1->4)-alpha-GlcNAc(PP-Dol)
dolichyl beta-D-glucosyl phosphate
Reaction output - small molecules:
Reactome.org link: R-HSA-4724330