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NIDA Proteomics Center
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Investigators
> Sreeganga Chandra
Neuronal Substrates Required for
Synapse Maintenance
Sreeganga Chandra, Program in Cellular Neuroscience, Neurodegeneration and
Repair, Department of Neurology,
Yale University
Synapses must be maintained throughout life to
provide normal brain functions and behavior. Synapse maintenance is not passive,
but an essential and actively regulated process in the adult brain. Drugs of
abuse have been shown to induce both structural and functional changes in
synapses, possibly by altering synapse maintenance pathways. Recently, several
molecules important for maintaining synapses have been identified. Cysteine
String Protein a
(CSPa)
and a-synuclein,
presynaptic proteins that are widely expressed in the brain, are two such
proteins. CSPa
is a co-chaperone that assembles with Hsc70 and the tetratricopeptide-repeat
protein SGT to form a chaperone complex on synaptic vesicles. Genetic studies in
mice have shown that CSPa
and a-synuclein
cooperate in the maintenance of synapses.
Our long term goals are to define the pathways
involved in synapse maintenance and to determine how they are altered in
neurological disorders or upon addiction. In this proposal, we seek to identify
the substrates of the CSPa
chaperone complex by a proteomic comparison of synaptic fractions derived from
wild type and CSPa
knockout brains. We have opted to use proteomic approaches as the low affinity
of the CSPa
chaperone complex precludes conventional biochemical purifications. For this
purpose, we will employ DIGE in concert with MALDI-MS/MS as well as iTRAQ. We
will also identify those substrates that are restored by overexpression of
a-synuclein
using similar methods. Validated substrates will be tested in dissociated
cultures for their roles in synapse maintenance and synaptic plasticity.
The diverse proteomic methodology and expertise of
the NIDA Neuroproteomic Center will greatly aid us in addressing our specific
aims. Through the planned experiments, we expect to identify key proteins that
participate in synapse maintenance. This is a first and necessary step to
understand the mechanisms underlying synapse maintenance and their contribution
to alterations in neural circuits upon drug use.
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