Enables NMDA glutamate receptor activity. Acts upstream of or within adult locomotory behavior; regulation of sensory perception of pain; and startle response. Located in synapse. Is expressed in brain. Human ortholog(s) of this gene implicated in developmental and epileptic encephalopathy 46. Orthologous to human GRIN2D (glutamate ionotropic receptor NMDA type subunit 2D). [provided by Alliance of Genome Resources, Apr 2022]