Intracellular Transport of Glycoproteins and Glycolipids

Abstract

Glycoproteins and glycolipids are primarily expressed at the cell surface of eukaryotic cells. Synthesis, intracellular sorting and transport of them is a major function of the endomembrane system. Although each of the various organelles of the endomembrane system is defined by a unique protein and lipid composition, these compartments are functionally connected by transport vesicles. Anterograde flow of material from the endoplasmic reticulum (ER) via the Golgi to the cell surface and retrograde flow of material from the cell surface towards endosomes/lysosomes, the Golgi and the ER occur simultaneously. It is, therefore, of particular importance that these processes are tightly regulated. Here we discuss molecular mechanisms of how transport vesicles may mediate protein and lipid sorting, thereby maintaining the integrity of the various organelles of the endomembrane system.