Enables ionotropic glutamate receptor binding activity. Involved in maintenance of postsynaptic specialization structure. Is active in glutamatergic synapse. Human ortholog(s) of this gene implicated in X-linked mental retardation with cerebellar hypoplasia and distinctive facial appearance. Orthologous to human OPHN1 (oligophrenin 1). [provided by Alliance of Genome Resources, Apr 2022]