This new project analyzes the molecular architecture of synapses in the mammalian brain with an initial focus on the postsynaptic density (PSD). Many molecular components of the PSD are known, but the PSD is so enormous (approximately 10 to the ninth Da) that new methods had to be developed to understand how its numerous molecular components are organized. A promising new approach begins by attaching PSDs to glass and then freezing and replicating them for electron microscopy. Manipulations prior to freeing allow identification and localization of particular components. These include: orientation of the PSDs on the glass by prior treatment of the glass with antibodies to one of their surface components; partial digestion of the PSDs on the glass with detergents; and labelling, after either of the above with antibodies marked by colloidal gold. Work to date clearly distinguishes the cleft side of the PSD, where NR-1 and PSD-95 are localized, from the cytoplasmic side where CaMKII is localized. Digestion of the cleft side reveals a lattice-like structure that forms the core of the PSD; this lattice labels heavily for PSD-95. The distributions of spectrin and actin with the PSD are currently being investigated, and the distribution of CaMKII is the subject of another project. It is now apparent that the spatial distributions of components of the PSD are an important aspect of PSD function.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Intramural Research (Z01)
Project #
1Z01NS002972-01
Application #
6111979
Study Section
Special Emphasis Panel (LN)
Project Start
Project End
Budget Start
Budget End
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
City
State
Country
United States
Zip Code
Mullasseril, Praseeda; Dosemeci, Ayse; Lisman, John E et al. (2007) A structural mechanism for maintaining the 'on-state'of the CaMKII memory switch in the post-synaptic density. J Neurochem 103:357-64
Tao-Cheng, J-H (2007) Ultrastructural localization of active zone and synaptic vesicle proteins in a preassembled multi-vesicle transport aggregate. Neuroscience 150:575-84
Tao-Cheng, Jung-Hwa; Gallant, Paul E; Brightman, Milton W et al. (2007) Structural changes at synapses after delayed perfusion fixation in different regions of the mouse brain. J Comp Neurol 501:731-40
Dosemeci, Ayse; Makusky, Anthony J; Jankowska-Stephens, Ewa et al. (2007) Composition of the synaptic PSD-95 complex. Mol Cell Proteomics 6:1749-60
Tavakoli-Nezhad, Mahboubeh; Tao-Cheng, Jung-Hwa; Weaver, David R et al. (2007) PER1-like immunoreactivity in oxytocin cells of the hamster hypothalamo-neurohypophyseal system. J Biol Rhythms 22:81-4
Chen, Xiaobing; Vinade, Lucia; Leapman, Richard D et al. (2005) Mass of the postsynaptic density and enumeration of three key molecules. Proc Natl Acad Sci U S A 102:11551-6
Tao-Cheng, J-H; Vinade, L; Winters, C A et al. (2005) Inhibition of phosphatase activity facilitates the formation and maintenance of NMDA-induced calcium/calmodulin-dependent protein kinase II clusters in hippocampal neurons. Neuroscience 130:651-6
DeGiorgis, Joseph A; Jaffe, Howard; Moreira, Jorge E et al. (2005) Phosphoproteomic analysis of synaptosomes from human cerebral cortex. J Proteome Res 4:306-15
Otmakhov, Nikolai; Tao-Cheng, Jung-Hwa; Carpenter, Stephen et al. (2004) Persistent accumulation of calcium/calmodulin-dependent protein kinase II in dendritic spines after induction of NMDA receptor-dependent chemical long-term potentiation. J Neurosci 24:9324-31
Jaffe, H; Vinade, L; Dosemeci, A (2004) Identification of novel phosphorylation sites on postsynaptic density proteins. Biochem Biophys Res Commun 321:210-8

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