Fig. 1: Cellular regulation and representation of glycans.
From: Structure, function, and pathology of protein O-glucosyltransferases
Depending on the intracellular compartments, mechanisms altering the intracellular location of glycosyltransferases and glycosidases can influence and regulate glycans modfication. A Secretory glycosylation occurs mainly in the ER and Golgi apparatus for secreted or transmembrane proteins where glycosyltransferases add and extend glycan modification in an ordered sequential manner. Cellular receptors and secretory proteins are transported to the cell surface and extracellular space, respectively. B Intracellular glycosylation involves the addition of glycans by OGT to proteins that reside mainly in the cytoplasm and nucleus. This modification of a Ser/Thr residue has a short lifetime and is cleaved by OGA, providing a target site for the second same modification or phosphorylation of Ser/Thr.
