How the Golgi works: a cisternal progenitor model.

The Golgi complex is a central processing compartment in the secretory pathway of eukaryotic cells. This essential compartment processes more than 30% of the proteins encoded by the human genome, yet we still do not fully understand how the Golgi is assembled and how proteins pass through it. Recent advances in our understanding of the molecular basis for protein transport through the Golgi and within the endocytic pathway provide clues to how this complex organelle may function and how proteins may be transported through it. Described here is a possible model for transport of cargo through a tightly stacked Golgi that involves continual fusion and fission of stable, "like" subcompartments and provides a mechanism to grow the Golgi complex from a stable progenitor, in an ordered manner.