The dynamics of synaptic scaffolds

Complex functions of the central nervous system such as learning and memory are believed to result from the modulation of the synaptic transmission between neurons. The sequence of events leading to the fusion of synaptic vesicles at the presynaptic active zone and the detection of this signal at the postsynaptic density involve the activity of ion channels and neurotransmitter receptors. Their accumulation and dynamic exchange at synapses are dependent on their interaction with synaptic scaffolds. These are synaptic structures composed of adaptor proteins that provide binding sites for receptors and channels as well as other synaptic proteins. While in its entirety the synaptic scaffold is a relatively stable structure, individual adaptor proteins exchange at a fast time scale. These properties of scaffolds help to ensure the stability of synaptic transmission while permitting the modulation of synaptic strength. Here, we review the dynamics of the synaptic scaffold and of adaptor proteins in relation to their roles in the organisation of the synapse as well as in the clustering and trafficking of receptor proteins. BioEssays 30:1062-1074, 2008. (C) 2008 Wiley Periodicals, Inc.