Glycosylation network mapping and site-specific maturation in vivo

Glycoprotein processing along a complex highly compartmentalized pathway is a hallmark of eukaryotic cells. We followed the kinetics of intracellular, site-specific glycan processing of a model protein with five distinct N-glycosylation sites and deduced a mathematical model of the secretory pathway that describes a com-plex set of processing reactions localized in defined intracellular compartments such as the endoplasmic reticulum the Golgi, or the lysosome. The model was able to accommodate site-specific N-glycan processing and we identified phos-phorylated glycan structures of the mannose-6-phosphate pathway responsible for the lysosomal sorting of the glycoprotein. Importantly, our model protein can take different routes of the cellular secretory pathway, resulting in an increased glycan complexity of the secreted protein.

Automated summary

Glycoprotein processing is a complex and compartmentalized pathway in eukaryotic cells. We studied the kinetics of glycan processing of a model protein and developed a mathematical model of the secretory pathway. Our model revealed the importance of phosphorylated glycan structures in lysosomal sorting and showed that the model protein can take different routes of the cellular secretory pathway, resulting in increased glycan complexity of the secreted protein.