GYS2 catalyzes the incorporation of phosphoglucose into glycogen-GYG2

Stable Identifier
Reaction [transition]
Homo sapiens
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Glycogen synthase 2 (GYS2) catalyzes the incorporation of phosphoglucose into the glycogen-GYG1 molecules with which it is associated in a cytosolic glycogen granule. This reaction occurs at a low rate, yielding approximately one molecule of glucose phosphorylated at its C2, C3, or C6 positions incorporated into a growing glycogen polymer per ten thousand glucose molecules incorporated (DePaoli-Roach et al. 2015; Irimia et al. 2015; Nitschke et al. 2013; Tagliabracci et al. 2011). The function of these small amounts of phosphoglucose in normal glycogen remains to be established. This reaction has been characterized in muscle cells, where it is catalyzed by the homologous GYS1 enzyme. The occurrence of the reaction in liver, catalyzed by GYS2, can be inferred from the fact that in the absence of the enzyme EMP2A (laforin) that removes these phosphate groups, abnormally phosphorylated glycogen accumulates in both tissues (Worby et al. 2008).

Literature References
PubMed ID Title Journal Year
25416783 Glycogen phosphomonoester distribution in mouse models of the progressive myoclonic epilepsy, Lafora disease

Ishihara, M, Segvich, DM, Heiss, C, Roach, PJ, Contreras, CJ, Azadi, P, DePaoli-Roach, AA

J. Biol. Chem. 2015
18070875 Malin decreases glycogen accumulation by promoting the degradation of protein targeting to glycogen (PTG)

Gentry, MS, Worby, CA, Dixon, JE

J. Biol. Chem. 2008
23663739 Hyperphosphorylation of glucosyl C6 carbons and altered structure of glycogen in the neurodegenerative epilepsy Lafora disease

Zhao, X, Schmieder, P, Wang, P, Wang, T, Awrey, DE, Girard, JM, Heydenreich, M, Nitschke, F, Kleinpeter, E, Steup, M, Turnbull, J, Minassian, BA, Israelian, J

Cell Metab. 2013
21356517 Phosphate incorporation during glycogen synthesis and Lafora disease

Ishihara, M, Hurley, TD, Glushka, J, Heiss, C, Karthik, C, Roach, PJ, Contreras, CJ, Tagliabracci, VS, DePaoli-Roach, AA, Azadi, P

Cell Metab. 2011
26216881 Muscle Glycogen Remodeling and Glycogen Phosphate Metabolism following Exhaustive Exercise of Wild Type and Laforin Knockout Mice

Segvich, DM, Meyer, CM, Roach, PJ, Irimia, JM, Tagliabracci, VS, DePaoli-Roach, AA

J. Biol. Chem. 2015
Catalyst Activity

glycogen synthase activity, transferring glucose-1-phosphate of PPP1R3C:glycogen-GYG2:GYS2-a tetramer [cytosol]

Orthologous Events
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