Asymmetry Between Pre- and Postsynaptic Transient Nanodomains Shapes Neuronal Communication

Synaptic transmission and plasticity are shaped by the dynamic reorganization of signaling molecules within pre- and postsynaptic compartments. The nanoscale organization of key effector molecules has been revealed by single-particle trajectory (SPT) methods. Interestingly, this nanoscale organization is highly heterogeneous. For example, presynaptic voltage-gated calcium channels (VGCCs) and postsynaptic ligand-gated ion channels such as AMPA receptors (AMPARs) are organized into so-called nanodomains where individual molecules are only transiently trapped. These pre- and postsynaptic nanodomains are characterized by a high density of molecules but differ in their molecular organization and stability within the synaptic membrane. We review the main properties of these nanodomains, as well as the methods developed to extract parameters from SPT experiments. We discuss how such molecular dynamics influences synaptic transmission. The nanoscale organization of active synapses opens new insights into the dynamics and turnover of molecules as well as casting light on their contributions to signal transfer between individual neurons.