SH3 and multiple ankyrin repeat domains protein 1 (Shank1) is an adaptor protein in the postsynaptic density (PSD) of excitatory synapses that interconnects receptors of the postsynaptic membrane including NMDA-type and metabotropic glutamate receptors via complexes with GKAP/PSD-95 and Homer, as well as in the actin based cytoskeleton. Shank1 plays a role in the structural and functional organization of the dendritic spine and synaptic junction. Shank1 is expressed in the brain, particularly in the amygdala, hippocampus, substantia nigra and thalamus.