Movement of proteins destined for membranes or secretion. After synthesis on ribosomes of the rough ER (see Figure 18-1) and targeting to the ER lumen, proteins travel in transport vesicles through the Golgi complex. Within the Golgi complex, the proteins may be further modified before they are sorted and shipped to their final destinations in secretory granules (for export from the cell) or transport vesicles (for further transport within the cell).