Critical role of cortical vesicles in dissecting regulated exocytosis : overview of insights into fundamental molecular mechanisms

Regulated exocytosis is one of the defining features of eukaryotic cells, underlying many conserved and essential functions. Definitively assigning specific roles to proteins and lipids in this fundamental mechanism is most effectively accomplished using a model system in which distinct stages of exocytosis can be effectively separated. Here we discuss the establishment of sea urchin cortical vesicle fusion as a model to study regulated exocytosis-a system in which the docked, release-ready, and late Ca2+-triggered steps of exocytosis are isolated and can be quan-titatively assessed using the rigorous coupling of functional and molecular assays. We provide an overview of the in-sights this has provided into conserved molecular mecha-nisms and how these have led to and integrate with findings from other regulated exocytotic cells.