Synaptogenesis: insights from worm and fly

Synapse formation is the ultimate step in wiring a nervous system. Synapses are remarkably diverse in size and shape, and are regulated dynamically. Recently, live observations combined with ultrastructural analysis have revealed many details of the cellular interactions that precede synapse formation. Genetic screens in Caenorhabditis elegans and Drosophila have implicated signaling pathways that may involve small G-proteins, ubiquitin-mediated protein degradation and selective cell adhesion in target recognition, synaptic assembly and growth.