Enables neurotransmitter transmembrane transporter activity. Involved in regulation of synaptic vesicle fusion to presynaptic active zone membrane and secretion by cell. Located in Schaffer collateral - CA1 synapse; glutamatergic synapse; and postsynapse. Part of SNARE complex. Is active in calyx of Held. Is expressed in nervous system; retina; and tongue. Human ortholog(s) of this gene implicated in developmental and epileptic encephalopathy 63. Orthologous to human CPLX1 (complexin 1). [provided by Alliance of Genome Resources, Apr 2022]