EPM2A dimer dephosphorylates phosphoglycogen-GYG2

Stable Identifier
Reaction [transition]
Homo sapiens
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EPM2A (laforin), associated with PPP1R3C (protein phosphatase 1 regulatory subunit 3C, PTG) and phosphoglycogen-GYG2 in a cytosolic glycogen particle, catalyzes the dephosphorylation of phosphoglycogen (Tagliabracci et al. 2007). This reaction is inferred from the activity of EPM2A on phosphoglycogen-GYG1, and from the fact that in the absence of normal EPM2A activity, abnormally phosphorylated forms of both glycogen-GYG1 and glycogen-GYG2 accumulate in cells. The catalytically active form of EPM2A has been shown to be a homodimer (Raththagala et al. 2015; Sankhala et al. 2015).

Literature References
PubMed ID Title Journal Year
25544560 Structural mechanism of laforin function in glycogen dephosphorylation and lafora disease

Parker, MW, Husodo, S, Bridges, TM, Auger, KD, Hellman, LM, Turner, BD, Li, S, Hsu, S, Gentry, MS, Meekins, DA, Chakravarthy, S, Vander Kooi, CW, Brewer, MK, Paasch, BC, Woods, VL, Sherwood, AR, Wong, BK, Taylor, AO, Dukhande, VV, Raththagala, M, Sanz, P

Mol. Cell 2015
18040046 Laforin is a glycogen phosphatase, deficiency of which leads to elevated phosphorylation of glycogen in vivo

Girard, JM, Roach, PJ, Delgado-Escueta, AV, Tagliabracci, VS, Zhao, X, Skurat, AV, DePaoli-Roach, AA, Wang, W, Turnbull, J, Minassian, BA

Proc. Natl. Acad. Sci. U.S.A. 2007
25538239 Dimeric quaternary structure of human laforin

Cingolani, G, Sankhala, RS, Nitschke, F, Ho, L, Minassian, BA, Koksal, AC

J. Biol. Chem. 2015
Catalyst Activity

carbohydrate phosphatase activity of EPM2A:PPP1R3C:phosphoglycogen-GYG2:GYS2-a tetramer [cytosol]

Orthologous Events
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