Synapses have traditionally been thought to be fixed structural elements but work during the past decade has revealed the dynamic nature of synaptic endings in the brain. This project is to study a unique synapse residing in the mammalian retina, the ribbon synapse. This synapse resides in the photoreceptors, which transduce light energy into neural signals. The photoreceptor ribbon has an exceptionally large active zone and one of the highest rates of vesicular transmission of any synapse in the nervous system. It was first described over 50 years ago as a fixed structural member of the photoreceptor presynaptic terminal. The precise function of the ribbon remains unclear. A monoclonal antibody that recognizes synaptic ribbons in the retina (B16) has been developed in the PIs laboratory and used to isolate a family of retinal specific proteins. The function of these proteins in vesicular trafficking and signal transduction pathways at the photoreceptor ribbon synapse will be studied, the identity of the B16's epitope on the synaptic ribbon will be determined and determination of the amino acid sequence of the proteins composing the synaptic ribbon will be attempted. It is also proposed to study the circadian control of the morphological dynamics observed in the synaptic ribbon. NSF funding will continue to support a rich educational environment promoting hands-on research experience for high school students from the New England area, undergraduate and graduate students at Boston College, and undergraduates from other east coast universities has been established.