Glycogen phosphorylase In the liver, glucagon activates another G-protein-linked receptor that triggers a different cascade, resulting in the activation of Phospholipase C (PLC). PLC indirectly causes the release of calcium from the hepatocytes' endoplasmic reticulum into the cytosol. The increased calcium availability binds to the calmodulin subunit and activates glycogen phosphorylase kinase. Glycogen phosphorylase kinase activates glycogen phosphorylase in the same manner mentioned previously. Glycogen phosphorylase b is not always inactive in muscle, as it can be activated allosterically by AMP. An increase in AMP concentration, which occurs during strenuous exercise, signals energy demand. AMP activates glycogen phosphorylase b by changing its
Adult polyglucosan body disease People with adult polyglucosan body disease typically first experience signs and symptoms related to the condition between ages 30 and 60. APBD is an autosomal recessive disorder that is caused when a person inherits genes from both parents containing one or more loss-of-function mutations in the gene "GBE1" which encodes for glycogen branching enzyme, also called 1,4-alpha-glucan-branching enzyme. The "GBE1" gene provides instructions for making the glycogen branching enzyme. This enzyme is involved in the production of a complex sugar called glycogen, which is a major source of stored energy in the body. Most "GBE1" gene mutations result in a