Figure 1.

The TGN is a meeting point where conventional and unconventional routes of intracellular transport merge. To illustrate this point, the classical biosynthetic pathway from the ER to the cell surface is depicted with green arrows. Alternative transport routes by which various large cargos such as HSV-1, chylomicrons, procollagen and some viruses that assemble in the cytoplasm reach the TGN are indicated by red arrows. In addition, the TGN is not only a merging point for molecules newly synthesized but also for proteins recycled from organelles along the endo-lysosomal system (shown with blue arrows). At the TGN, large and small cargos merge and are sorted towards the cell surface (green arrows) and various endosomal compartments (yellow arrows). Dotted green arrows illustrate the uncertainty as to whether large cargo, in particular viruses, share the PKD mediated pathway with smaller cargo or whether they monopolizes it.