Derangements in synaptic transmission are part of the pathology of several neurological and mental diseases including epilepsy, schizophrenia, depression, and Alzheimer's disease. We are studying the molecular mechanisms underlying regulation of synaptic transmission. Here we propose to study regulatory pathways at glutamatergic synapses governed by Ca2+/calmodulin-dependent protein kinase II (CaMKII). CaMKII is concentrated in the postsynaptic density where it can be activated by Ca 2+ influx through NMDA receptors. The proposal focuses on two principal postsynaptic substrates of CaMKII, SynGAP, a Ras GTPase-activating protein that is concentrated in the postsynaptic density, and densin, a proposed docking site for CaMKII. In the First Aim, we will test the hypothesis that synGAP participates in regulation of the cytoskeleton at synapses in brain slices. We have previously shown that synGAP helps to regulate the spine cytoskeleton during synapse formation in cultured neurons, and that the location and activation of the kalirin/PAK kinase pathway is altered in hippocampal slices heterozygous for synGAP. We will use slices from wild type and synGAP deficient mutants to map the role of synGAP in this and related pathways following synaptic stimulation. In the Second Aim, we will use electrophysiological studies in hippocampal slices from wild type and conditional synGAP deficient mice to investigate whether the effects of synGAP deficiency on LTP are a result of developmental abnormalities or of acute loss of synGAP. We will also test the hypothesis that synGAP participates in regulation of the modulation of dendritic excitability by MAP kinase. In the Third Aim, we will examine recruitment of CaMKII to the PSD in neuronal cultures prepared from knock-in mice that are missing the carboxyl terminal tails of the NR2A and NR2B subunits of the NMDA receptor. We will also examine recruitment of CaMKII in these cultures after introducing recombinant forms of the intracellular tails of densin, or reducing the expression of densin by introduction of siRNA. In the Fourth Aim, we propose to determine the physiological importance of densin, and test the hypothesis that densin is a docking site for CaMKII in the PSD by constructing knockout and conditional knockout mutants of densin.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS017660-23A2
Application #
6870594
Study Section
Synapses, Cytoskeleton and Trafficking Study Section (SYN)
Program Officer
Liu, Yuan
Project Start
1981-07-01
Project End
2008-11-30
Budget Start
2004-12-07
Budget End
2005-11-30
Support Year
23
Fiscal Year
2005
Total Cost
$345,950
Indirect Cost
Name
California Institute of Technology
Department
Type
Schools of Arts and Sciences
DUNS #
009584210
City
Pasadena
State
CA
Country
United States
Zip Code
91125
Wang, Shiyi; Stanika, Ruslan I; Wang, Xiaohan et al. (2017) Densin-180 Controls the Trafficking and Signaling of L-Type Voltage-Gated Cav1.2 Ca2+ Channels at Excitatory Synapses. J Neurosci 37:4679-4691
Carlisle, Holly J; Luong, Tinh N; Medina-Marino, Andrew et al. (2011) Deletion of densin-180 results in abnormal behaviors associated with mental illness and reduces mGluR5 and DISC1 in the postsynaptic density fraction. J Neurosci 31:16194-207
Carlisle, Holly J; Manzerra, Pasquale; Marcora, Edoardo et al. (2008) SynGAP regulates steady-state and activity-dependent phosphorylation of cofilin. J Neurosci 28:13673-83
Zhou, Yu; Takahashi, Eiki; Li, Weidong et al. (2007) Interactions between the NR2B receptor and CaMKII modulate synaptic plasticity and spatial learning. J Neurosci 27:13843-53
Ouyang, Yannan; Wong, Michael; Capani, Francisco et al. (2005) Transient decrease in F-actin may be necessary for translocation of proteins into dendritic spines. Eur J Neurosci 22:2995-3005
Knuesel, Irene; Elliott, Abigail; Chen, Hong-Jung et al. (2005) A role for synGAP in regulating neuronal apoptosis. Eur J Neurosci 21:611-21
Vazquez, Luis E; Chen, Hong-Jung; Sokolova, Irina et al. (2004) SynGAP regulates spine formation. J Neurosci 24:8862-72
Oh, Jeong S; Manzerra, Pasquale; Kennedy, Mary B (2004) Regulation of the neuron-specific Ras GTPase-activating protein, synGAP, by Ca2+/calmodulin-dependent protein kinase II. J Biol Chem 279:17980-8
Walikonis, R S; Oguni, A; Khorosheva, E M et al. (2001) Densin-180 forms a ternary complex with the (alpha)-subunit of Ca2+/calmodulin-dependent protein kinase II and (alpha)-actinin. J Neurosci 21:423-33
Kennedy, M B (2000) Signal-processing machines at the postsynaptic density. Science 290:750-4

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