Figure 1.

A, schematic of laforin. CBM, carbohydrate-binding module; DSP, dual-specificity phosphatase. B, glycogen is a soluble branched glucose polymer. The EPM2A gene encodes the glycogen phosphatase laforin, and EPM2B encodes the E3 ubiquitin ligase malin. Mutations in EPM2A or EPM2B result in glycogen that is hyperphosphorylated (red circles) and has disrupted glucose chain branching. This abnormal, less-soluble glycogen aggregates to form the Lafora bodies that cause Lafora disease. C, schematic of malin. RING, E2 interacting domain; NHL, protein interaction domain.