The mechanisms by which the ultimate pattern of synaptic connections arises in the CNS is one of the great unanswered questions in neurobiology. Some insights into this question may be gleaned from the structure of synaptic junctions. Each excitatory CNS synapse is an asymmetric cell-cell junction, with very different sets of molecules clustered on the respective sides of the junction. How the different sets of molecules target to synaptic membranes and remain in direct apposition to each other is still not completely understood but trans-synaptic interactions must have an important role in this process and are also probably involved in the specification of synaptic connectivity. We hypothesize that the synaptic cleft contains a number of uncharacterized molecules important for trans-synaptic interactions. Identification of such molecules will shed new light on the role of pre-to-postsynaptic recognition in the maintenance of synaptic architecture and in the generation of connectivity. In this R21 proposal, we will use a targeted biochemical approach to identify the molecules that mediate trans-synaptic interactions, made possible by the PIs preliminary studies in which intact synaptic junctions were isolated from the CNS, preserving trans-synaptic molecules and their interactions.
In Aim 1, we will recover synaptic cleft proteins on isolated synaptic membranes by utilizing cell surface biotinylation and immobilized lectins. Recovered candidate synaptic cleft proteins will be electrophoresed and identified by mass spectrometry.
In Aim 2, we will develop antibodies to identified candidate synaptic cleft proteins for use at the light and EM levels to evaluate the synaptic localization of potential cleft proteins. Upon completion of these Aims, we expect to have in hand reagents corresponding to some of the most prominent synaptic cleft molecules. We will use these reagents to examine the role of cell-cell interactions in the initiation, maturation and plasticity of synaptic junctions and in the recruitment of other critical molecules to synaptic membranes.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21NS048367-02
Application #
6855109
Study Section
Neurodifferentiation, Plasticity, and Regeneration Study Section (NDPR)
Program Officer
Talley, Edmund M
Project Start
2004-07-01
Project End
2007-04-30
Budget Start
2005-05-01
Budget End
2007-04-30
Support Year
2
Fiscal Year
2005
Total Cost
$195,984
Indirect Cost
Name
Mount Sinai School of Medicine
Department
Neurosciences
Type
Schools of Medicine
DUNS #
078861598
City
New York
State
NY
Country
United States
Zip Code
10029
Phillips, Greg R; LaMassa, Nicole; Nie, Yan Mei (2017) Clustered protocadherin trafficking. Semin Cell Dev Biol 69:131-139
Jontes, James D; Phillips, Greg R (2006) Selective stabilization and synaptic specificity: a new cell-biological model. Trends Neurosci 29:186-91
Khaing, Zin Z; Fidler, Lazar; Nandy, Nina et al. (2006) Structural stabilization of CNS synapses during postnatal development in rat cortex. J Neurochem 98:471-80
Frank, Marcus; Ebert, Matthias; Shan, Weisong et al. (2005) Differential expression of individual gamma-protocadherins during mouse brain development. Mol Cell Neurosci 29:603-16
Phillips, Greg R; Florens, Laurence; Tanaka, Hidekazu et al. (2005) Proteomic comparison of two fractions derived from the transsynaptic scaffold. J Neurosci Res 81:762-75