Enables identical protein binding activity. Involved in several processes, including cerebellar granule cell differentiation; heterophilic cell-cell adhesion via plasma membrane cell adhesion molecules; and regulation of synapse assembly. Acts upstream of or within positive regulation of synapse assembly and protein secretion. Located in several cellular components, including glutamatergic synapse; parallel fiber to Purkinje cell synapse; and synaptic cleft. Is expressed in several structures, including central nervous system; limb; oral region epithelium; reproductive system; and sensory organ. Orthologous to human CBLN1 (cerebellin 1 precursor). [provided by Alliance of Genome Resources, Apr 2022]