Protein glycosylation and synaptic transmission: brain glycogen keeps them separated

Brain glycogen has long been regarded uniquely as a source of energetic support in situations of emergency or heightened activity. Recently, brain glycogen was found to contain a significant amount of glucosamine, which is used to sustain protein glycosylation. In this update, we highlight that glucosamine synthesis through the hexosamine pathway would subtract glutamine, which is indispensable for glutamate and GABA recycling.