Regulation of AMPAR synaptic clustering is important for establishing excitatory neurotransmission in development and for controlling the number of synaptic AMPARs during synaptic plasticity. Targeting of AMPARs to synaptic sites requires stargazin-PDZ protein interaction. nPIST, a PDZ protein, interacts with stargazin/AMPARs and is found in both the Golgi apparatus and the synapse, where it interacts with synaptic molecules such as glutamate receptor GluRd2. As such, nPIST is an excellent candidate for chaperoning the stargazin/AMPAR complex from the Golgi apparatus to the synapse, and may play a critical role in modulation of AMPAR synaptic clustering in plasticity. The goal of this proposal is to characterize the mechanisms by which nPIST regulates AMPAR synaptic delivery. ? ? ?