Proteomic Investigation of the Binding Agent between Liver Glycogen β Particles

Glycogen is a highly branched glucose
polymer which plays an important
role in glucose storage and the maintenance of blood sugar homeostasis.
The dimeric protein glycogenin can self-glucosylate to act as a primer
for glycogen synthesis, eventually resulting in small (∼20
nm diameter) glycogen β particles with a dimer of glycogenin
at their core. In the liver, glycogen is also found in the form of
α particles: large bound composites of many β particles.
Here, we provide evidence using qualitative and quantitative proteomics
and size-exclusion chromatography from healthy rat, mouse, and human
liver glycogen that glycogenin is the binding agent linking β
particles together into α particles.