POMT1:POMT2 transfers Man from Dol-P-Man to DAG1(30-653)

Stable Identifier
R-HSA-5615637
Type
Reaction [transition]
Species
Homo sapiens
Compartment
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Co-expression of both protein O-mannosyl-transferases 1 and 2 (POMT1 and POMT2; CAZy family GT39) is necessary for enzyme activity (Manya et al. 2004), that is mediating the transfer of mannosyl residues to the hydroxyl group of serine or threonine residues of proteins such as alpha-dystroglycan (DAG1; MIM:128239). This process occurs in the ER lumen and both POMT isozymes are ER membrane residents. DAG1 is a cell surface protein that plays an important role in the assembly of the extracellular matrix in muscle, brain, and peripheral nerves by linking the basal lamina to cytoskeletal proteins. Defects in POMT2 (MIM:607439) results in defective glycosylation of DAG1 and can cause severe congenital muscular dystrophy dystroglycanopathies ranging from a severe type A, MDDGA2 (brain and eye abnormalities; MIM:613150), through a less severe type B, MDDGB2 (congenital form with mental retardation; MIM:613156) to a milder type C, MDDGC2 (limb girdle form; MIM:603158) (Bertini et al. 2011, Wells 2013).

Literature References
PubMed ID Title Journal Year
23329833 The o-mannosylation pathway: glycosyltransferases and proteins implicated in congenital muscular dystrophy

Wells, L

J. Biol. Chem. 2013
14699049 Demonstration of mammalian protein O-mannosyltransferase activity: coexpression of POMT1 and POMT2 required for enzymatic activity

Manya, H, Chiba, A, Yoshida, A, Wang, X, Chiba, Y, Jigami, Y, Margolis, RU, Endo, T

Proc. Natl. Acad. Sci. U.S.A. 2004
22172424 Congenital muscular dystrophies: a brief review

Bertini, E, D'Amico, A, Gualandi, F, Petrini, S

Semin Pediatr Neurol 2011
Participants
Participant Of
Catalyst Activity
Catalyst Activity
Title
dolichyl-phosphate-mannose-protein mannosyltransferase activity of POMT1:POMT2 [endoplasmic reticulum membrane]
Physical Entity
Activity
Orthologous Events
Authored
Reviewed
Created