Glycogen (lysosomal)

Lysosomal glycogen refers to the storage form of the polysaccharide glycogen found within the lysosomal compartment of cells. Glycogen is a highly branched glucose polymer that serves as a critical energy reserve, primarily stored in the liver and muscle, but a fraction is also trafficked into lysosomes[4][5][2]. Lysosomal glycogen is degraded by the enzyme acid alpha-glucosidase (GAA), which hydrolyzes both α(1→4) and α(1→6) glycosidic linkages to release glucose, a process essential under certain physiological and pathological conditions[3][6][1]. Unlike cytosolic glycogen metabolism—which involves glycogen phosphorylase and debranching enzyme—lysosomal glycogen degradation relies exclusively on acid alpha-glucosidase (GAA)[1][6][2]. Deficiencies or mutations in GAA lead to the accumulation of lysosomal glycogen, most notably causing Pompe disease, a glycogen storage disorder characterized by progressive muscle weakness, cardiomegaly, and impaired cellular function due to toxic buildup of glycogen within lysosomes[3][2]. Lysosomal glycogen itself is not a molecular target (such as a receptor, enzyme, transporter, or signaling molecule), but rather a substrate acted upon by GAA. Thus, from the perspective of drug targeting and therapeutic intervention, the enzyme GAA (acid alpha-glucosidase) is the relevant molecular target—not glycogen itself. Summary of accuracy/appropriateness: The term “lysosomal glycogen” is not a canonical therapeutic target or a receptor but rather a substrate or storage molecule. The actual drug target for Pompe disease and related therapies is acid alpha-glucosidase (GAA), not lysosomal glycogen. For structured information mapping, "lysosomal glycogen" would be considered an entity of biological significance, but not a druggable target[1][3][6][2].

Other names

Lysosomal glycogenLysosomal glycogen storageGlycogen (in lysosome)