Molecular complexity at the synapse: new proteins and multiple isoforms detected in Drosophila

Synaptic transmission and its context-dependent modification are pivotal for all forms of information processing in the nervous system including learning and memory. The molecular components of the presynaptic nerve terminal are therefore under intensive study. Using a reverse genetic approach in Drosophila we have cloned the first invertebrate homologue to vertebrate synapsins and identified two new protein families, the "synapse-associated protein of 47 kD" (SAP47) and the cysteine string proteins (CSPs), which are conserved throughout higher eukaryotic evolution. Information on the molecular, cellular and systemic functions of these proteins and their isoforms is summarized in this review.