Stbd1 participation in glycogen metabolism and Stbd1 structure

Model for Stbd1 participation in glycogen metabolism and Stbd1 structure. A, classic cytosolic pathway of glycogen synthesis from glucose (Glc) via glucose-6-phosphate (Glc-6-P), glucose-1-phosphate (Glc-1-P) and the glucosyl donor UDP-glucose (UDP-Glc) is mediated by glycogenin (GN), glycogen synthase (GS) and branching enzyme (BE). Degradation to yield Glc-1-P is catalyzed by glycogen phosphorylase (Ph) and debranching enzyme (DBE). A second pathway for glycogen breakdown involves transfer to lysosomes where it is hydrolyzed to glucose by lysosomal α-glycosidase (GAA). From the results of this study, we propose that Stbd1 participates in the vesicular trafficking of glycogen, mediated also by its interaction with GABARABL1 (or maybe GABARAP). In a number of diseases and mouse models, abnormal glycogen deposits can be formed, some possibly with elements of membranes associated. B, a number of the enzymes involved in glycogen metabolism can be partially purified with glycogen. PhK, phosphorylase kinase; PP1, type 1 protein phosphatase; PTG and RGL, glycogen binding PP1 targeting subunits; PP1c, catalytic subunit of PP1; LF, laforin. Shown also is the proposed role for Stbd1, anchoring glycogen to an intracellular membrane and interacting with GABARAPL1 (G-L1).

Publication

Starch Binding Domain-containing Protein 1/Genethonin 1 Is a Novel Participant in Glycogen Metabolism. (2010) Sixin Jiang, et al. J Biol Chem. 2010 Nov 5;285(45):34960-34971. Figure: F8. All organisms Drosophila melanogaster Homo sapiens

Disease mentions