Invited Symposium: On/Off Switches for Nitric Oxide Synthases
Snowman, A.M. (Department of Neuroscience, Johns Hopkins University School of Medicine, USA)
Snyder, S.H. (Department of Neuroscience, Johns Hopkins University School of Medicine, USA)
Nitric oxide (NO) produced by neuronal nitric oxide synthase (nNOS) is important for NMDA receptor-dependent neurotransmitter release, neurotoxicity, and cGMP elevations. The coupling of NMDA receptor mediated calcium influx and nNOS activation is postulated to be due to a physical coupling of the receptor and the enzyme by an intermediary adaptor protein, PSD95, through a unique PDZ-PDZ domain interaction between PSD95 and nNOS. Here, we report the indentification of a novel nNOS-associated protein, CAPON, which is highly enriched in the brain and has numerous colocalizations with nNOS. CAPON interacts with the nNOS PDZ domain through its C terminus. CAPON competes with PSD95 for interaction with nNOS, and overexpression of CAPON results in a loss of PSD95/nNOS complexes in transfected cells. CAPON has a phosphotyrosine-binding domain in its N terminus. Here we also describe the purification of a PTB-binding protein which is enriched in synaptic vesicles. CAPON binds to this protein and nNOS is coupled to synaptic vesicles by this ternary interaction. The binding of nNOS to synaptic vesicles through CAPON may account for the highly potent effect of endogenously produced NO on synaptic vesicle release.
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|Jaffrey, S.R.; Snowman, A.M.; Snyder, S.H.; (1998). Targetting of Neuronal Nitric Oxide Synthase to the Cytosol and the Synapse by a Novel Adapter Protein, CAPON. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Invited Symposium. Available at URL http://www.mcmaster.ca/inabis98/garcia-cardena/jaffrey0890/index.html|
|© 1998 Author(s) Hold Copyright|