Endosome-to-Golgi transport pathways in physiological processes

The trans-Golgi network (TGN) is a major traffic hub of the cell, as it regulates membrane transport in the secretory pathway as well as receiving protein cargo by retrograde transport from endocytic compartments. Retrograde transport between endosomes and the TGN is essential for the recycling of membrane proteins which regulate a range of cellular and development functions. In addition, retrograde transport pathways are exploited by many bacterial toxins to mediate cytotoxicity and by some viral proteins to promote pathogenicity. Recent advances using a range of molecular cell biological strategies have identified multiple retrograde transport pathways each regulated by a distinct set of molecular machinery. Here we review recent advances in this field and highlight the importance of these transport pathways in a range of physiological processes.