Abstract
Formation of synaptic connections between nerve cells is the key to understanding neuronal development. Despite the wealth of in vitro information, fundamental questions regarding how synapses are formed in the mammalian brain remain unanswered. Glutamate receptor (GluR) δ2 selectively expressed in cerebellar Purkinje cells is essential for synaptic formation in vivo. We showed that the trans-synaptic interaction of postsynaptic GluRδ2 and presynaptic neurexins through secreted cerebellin precursor protein 1 (Cbln1) mediates cerebellar synapse formation. We also demonstrated that GluRδ2 triggers synapse formation by tetramerization of neurexins through Cbln1. These finding provide a molecular insight into the mechanism of synapse formation in the brain.
