Enables ionotropic glutamate receptor binding activity; protein C-terminus binding activity; and scaffold protein binding activity. A structural constituent of postsynaptic density. Involved in several processes, including learning or memory; modulation of chemical synaptic transmission; and postsynapse organization. Acts upstream of or within several processes, including MAPK cascade; negative regulation of actin filament bundle assembly; and regulation of AMPA glutamate receptor clustering. Located in glutamatergic synapse and neuron spine. Is extrinsic component of cytoplasmic side of plasma membrane. Is expressed in brain and cerebral cortex. Used to study Phelan-McDermid syndrome; autism spectrum disorder; and schizophrenia. Human ortholog(s) of this gene implicated in Phelan-McDermid syndrome and schizophrenia 15. Orthologous to human SHANK3 (SH3 and multiple ankyrin repeat domains 3). [provided by Alliance of Genome Resources, Apr 2022]