Molecular cloning of synaphins/complexins, cytosolic proteins involved in transmitter release, in the electric organ of an electric ray (Narke japonica)

Synaphins/complexins are cytosolic proteins associated with the docking/fusion complex crucial to transmitter release. The electric organ of the electric ray Narke japonica contained at least two kinds of synaphins as revealed by immunoblotting. cDNAs for three synaphins were cloned from a cDNA library prepared from the electric lobe where cell bodies of electromotor nerves innervating the electric organ exist. The proteins encoded by these cDNAs were named Nj-synaphins la, lb and 2 on the basis of their high homologies (83-93%) to mammalian synaphins 1 and 2. Nj-Synaphins were immunoprecipitated by an anti-syntaxin monoclonal antibody together with syntaxin SNAP-25 and VAMP (synaptobrevin), suggesting the presence of a docking/fusion complex similar to that in the mammalian brain.