Electron micrographs of the Golgi apparatus typically show a series of
flat cisternae stacked together, surrounded by numerous vesicles and
tubules. Palade and colleagues established in the 1960s that secretory
proteins pass through this morphologically complex organelle as they
travel from the endoplasmic reticulum to the cell surface. However, th
e precise mechanism of transport through the cisternal stack has prove
n a controversial issue. Recent advances in identifying the molecules
responsible for this traffic suggest that the solution may not be far
away.