Synaptic Adhesion Molecules
Synaptic function is dependent on protein:protein interactions, including those mediated by synaptic adhesion molecules (SAMs). SAMs are multifunctional, membrane-anchored proteins that are localized to presynaptic and postsynaptic neuronal membranes. Direct interactions between the extracellular domains of SAMs bridge the two opposing membranes and form two types of adhesive structures including synaptic junctions and puncta adherentias. Synaptic junctions are associated with presynaptic active zones where neurotransmitters are released as well as postsynaptic densities where neurotransmitter receptors are localized. While synaptic junctions maximize neurotransmission, puncta adherentias contribute to structural integrity of the synapse.