Presynaptic Development: Functional and Morphological Organization

Chemical synapses are asymmetric intercellular junctions typically formed between axonal and dendritic processes of neurons. The presynaptic side of synapses possesses synaptic vesicles containing neurotransmitters clustered around a protein-dense region called the active zone. Recent studies have identified several molecular components of the active zone and the protein-protein interactions that link the active zone to synaptic vesicles and the release machinery. Another key advance has been the identification of specific synaptic cell adhesion molecules that initiate synapse assembly and bridge the synaptic cleft in mature synapses. Functional studies have also been instrumental in defining distinct stages of presynaptic assembly and maturation during development.