Selecting synapse start sites

In the central nervous system, synapses form when specific organelles and proteins are recruited to a site where the axon of one cell contacts a dendrite of another. But how do the cells coordinate the extracellular formation of a contact with the intracellular movement of organelles? On page 649, Sytnyk et al. describe the interaction of neural cell adhesion molecule (NCAM) clusters with intracellular organelle aggregates derived from the trans-Golgi network (TGN). The work is the first demonstration that recognition molecules such as NCAM directly link extracellular signals to intracellular organelle movement at developing synapses.

As NCAM was believed to stabilize the contact structure in synaptogenesis, the authors examined the movements and localization of NCAM and the TGN organelles in cultured hippocampal neurons. The results show that spectrin links the TGN organelles directly to clusters of...