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Citron binds to PSD-95 at glutamatergic synapses on inhibitory neurons in the hippocampus

Zhang, Wandong and Vazquez, Luis and Apperson, Michelle and Kennedy, Mary B. (1999) Citron binds to PSD-95 at glutamatergic synapses on inhibitory neurons in the hippocampus. Journal of Neuroscience, 19 (1). pp. 96-108. ISSN 0270-6474. PMCID PMC6782379. doi:10.1523/JNEUROSCI.19-01-00096.1999.

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Synaptic NMDA-type glutamate receptors are anchored to the second of three PDZ (PSD-95/Discs large/ZO-1) domains in the postsynaptic density (PSD) protein PSD-95. Here, we report that citron, a protein target for the activated form of the small GTP-binding protein Rho, preferentially binds the third PDZ domain of PSD-95. In GABAergic neurons from the hippocampus, citron forms a complex with PSD-95 and is concentrated at the postsynaptic side of glutamatergic synapses. Citron is expressed only at low levels in glutamatergic neurons in the hippocampus and is not detectable at synapses onto these neurons. In contrast to citron, p135 SynGAP, an abundant synaptic Ras GTPase-activating protein that can bind to all three PDZ domains of PSD-95, and Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) are concentrated postsynaptically at glutamatergic synapses on glutamatergic neurons. CaM kinase II is not expressed and p135 SynGAP is expressed in less than half of hippocampal GABAergic neurons. Segregation of citron into inhibitory neurons does not occur in other brain regions. For example, citron is expressed at high levels in most thalamic neurons, which are primarily glutamatergic and contain CaM kinase II. In several other brain regions, citron is present in a subset of neurons that can be either GABAergic or glutamatergic and can sometimes express CaM kinase II. Thus, in the hippocampus, signal transduction complexes associated with postsynaptic NMDA receptors are different in glutamatergic and GABAergic neurons and are specialized in a way that is specific to the hippocampus.

Item Type:Article
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URLURL TypeDescription CentralArticle
Kennedy, Mary B.0000-0003-1369-0525
Additional Information:© 1998 Society for Neuroscience. Received Aug. 25, 1998; revised Oct. 8, 1998; accepted Oct. 20, 1998. This work was supported by United States Public Health Service Grant NS28710 and National Science Foundation Grant GER-9023446. We thank Leslie Schenker for preparation of cultures and help with experiments, Hans-Christian Kornau and Peter Seeburg for the PSD-95 fragment library, Dr. Susan Catalano for help with preparation of the figures, and Kathleen Branson for help with preparation of this manuscript
Funding AgencyGrant Number
Subject Keywords:citron; PSD-95; inhibitory neurons; postsynaptic density; synaptic transmission; signal transduction
Issue or Number:1
PubMed Central ID:PMC6782379
Record Number:CaltechAUTHORS:20120424-154217503
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Official Citation:Citron Binds to PSD-95 at Glutamatergic Synapses on Inhibitory Neurons in the Hippocampus. Wandong Zhang, Luis Vazquez, Michelle Apperson, Mary B. Kennedy. Journal of Neuroscience 1 January 1999, 19 (1) 96-108; DOI: 10.1523/JNEUROSCI.19-01-00096.1999
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:30323
Deposited By: Melanie Stefan
Deposited On:25 Apr 2012 18:40
Last Modified:09 Nov 2021 19:45

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