Protein Glycosylation Animation Close Animation showing how glycoproteins are produced within cells. The transfer of N-glycan chains begins during the assembly of the protein itself in a cellular organelle called endoplasmic reticulum (ER). On its way to its destination, the glycoprotein transits through another cellular structure called Golgi apparatus, where it is further decorated in by the addition of more carbohydrates. The same protein produced in different cell types usually carry distinct carbohydrate chains. Animation provided by Dr. Thierry Hennet.