Squid photoreceptor terminals synthesize calexcitin, a learning related protein.

摘要

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.