Enables ephrin receptor binding activity. Involved in several processes, including ephrin receptor signaling pathway; negative regulation of dendritic spine morphogenesis; and synapse pruning. Is active in glutamatergic synapse. Is expressed in several structures, including brain; eye; female reproductive system; forelimb; and liver. Orthologous to human NGEF (neuronal guanine nucleotide exchange factor). [provided by Alliance of Genome Resources, Apr 2022]