title: Squid photoreceptor terminals synthesize calexcitin, a learning related protein.
abstract: Nerve endings of squid photoreceptor neurons generate large synaptosomes upon homogenization of the optic lobe. Using several independent methods, these presynaptic structures have been shown to synthesize a wealth of soluble, cytoskeletal and nuclear encoded mitochondrial proteins, and to account for essentially all the translation activity of the synaptosomal fraction. We are now presenting evidence that calexcitin, a learning related, Ca(2+)-binding protein of the B photoreceptors of Hermissenda crassicornis (a mollusk), is synthesized and subjected to post-translational modifications in the squid photoreceptor terminals. In view of the essential role of presynaptic protein synthesis in long-term memory formation in Aplysia, our data suggest that a comparable role may be played by calexcitin synthesized in the squid photoreceptor terminals.
authors.affiliation: Dipartimento di Fisiologia Generale e Ambientale, Università di Napoli "Federico II", Via Mezzocannone 8, 80134, Naples, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Eyman
authors.forename: Marianna
authors.initials: M
authors.lastname: Crispino
authors.forename: Barry B
authors.initials: BB
authors.lastname: Kaplan
authors.forename: Antonio
authors.initials: A
authors.lastname: Giuditta
mesh_terms: D000818:Animals; D015153:Blotting, Western; D029742:Caenorhabditis elegans Proteins; D002135:Calcium-Binding Proteins / Q000096:biosynthesis*; D049832:Decapodiformes; D019204:GTP-Binding Proteins / Q000096:biosynthesis*; D007858:Learning; D009411:Nerve Endings / Q000378:metabolism*; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D029742:Caenorhabditis elegans Proteins; D002135:Calcium-Binding Proteins; D019204:GTP-Binding Proteins; C102751:cex-2 protein, C elegans