Distinct SAP102 and PSD-95 nano-organization defines multiple types of synaptic scaffold protein domains at single synapses.

SAP102 and PSD-95 are two key members of the MAGUK family of synaptic scaffold proteins that are critical for synapse development, maintenance, and modification during plasticity. Because PSD-95 has a highly complex subsynaptic nanostructure that impacts synaptic function, we asked if SAP102 is similarly organized into nanoclusters at individual synapses and how it relates to PSD-95 within synapses. We found that SAP102 forms subsynaptic nanoclusters with unique properties, and that within individual synapses proteins both concentrate into overlapping nanodomains, as well as form MAGUK-specific nanodomains. This demonstrates that organization of synaptic proteins into nanoclusters is likely to be maintained within the family of MAGUK proteins and reveals potential mechanism for specializing functions within individual synapses based on scaffold protein nanodomains.