This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. PSD-95 is a prototypical scaffold enriched in the postsynaptic density (PSD) of excitatory synapses and plays an important role in localization of glutamate receptors in the synapse and synaptic plasticity. Mechanisms regulating PSD-95 levels in the synapse are not well understood. The aim of this project is to identify novel PSD proteins involved in regulation of PSD-95 and elucidate their roles in synaptic development, function, and plasticity.