SynCAM and sidekick synchronize synapse synthesis

Learning, memory, forgetting—these are functions of synapses, the connections between nerve cells. Although studies of nerve cell differentiation, migration, and axonal pathfinding have put neurons in the right neighborhood, considerable work is needed to understand the smaller scale problems of choosing an axon partner and forming a synapse.

Synapse formation requires SynCAM, according to Thomas Biederer, Thomas Südhof, and colleagues (University of Texas Southwestern Medical Center, Dallas, TX), who found that SynCAM mediated cell adhesion and initiated synapse differentiation. Expression of SynCAM in nonneuronal cells both induced neighboring neurons to form functional presynaptic terminals and, if glutamate receptors were added to the mix, induced postsynaptic membranes capable of electrical responses to glutamate. According to Biederer, the widely expressed SynCAM is one of four closely related proteins that may initiate synapse formation throughout the central nervous...