This program project consisting of three projects and three cores ainns at elucidating molecular mechanisms that are responsible for membrane fusion in presynaptic exocytosis. The molecular machine at the center of this process is the SNARE complex that assembles from its components during presynaptic membrane fusion. Energy derived from SNARE complex folding and assembly drives the kinetically blocked fusion of vesicle and cell membrane bilayers. Regulatory proteins including synaptotagmin, complexin, and Munc18 render SNARE complex formation and fusion sensitive to calcium and control SNARE assembly and fusion by mechanisms that are still poorly understood at the structural mechanistic level. A group of talented biochemists, structural biologists, biophysicists, and cell biologists has been asembled in this program project to jointly tackle several key questions of presynaptic membrane fusion. SNARE assembly and fusion intermediates will be structurally and functionally characterized and correlated;the structural and biophysical basis of the regulation of SNARE assembly by accessory proteins and its coupling to fusion will be elucidated;and the evolution of the supramolecular architecture of nascent and mature fusion pores will be examined. The approaches range from high-resolution molecular spectroscopy and structural biology to biochemical and molecular biological dissections of the process with judiciously selected mutants to advanced optical and cell biological methods.

Public Health Relevance

Fusion of synaptic vesicles with the cell membranes of neurons is a key element of synaptic transmission. Defects in synaptic transmission lead to epilepsy, depression, and other neurological disorders. Understanding the molecular mechanism and structural basis of membrane fusion at the synapse will ultimately help to combat these diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Program Projects (P01)
Project #
5P01GM072694-08
Application #
8507740
Study Section
Special Emphasis Panel (ZRG1-BCMB-S (40))
Program Officer
Chin, Jean
Project Start
2005-04-01
Project End
2016-06-30
Budget Start
2013-07-01
Budget End
2014-06-30
Support Year
8
Fiscal Year
2013
Total Cost
$1,099,991
Indirect Cost
$321,333
Name
University of Virginia
Department
Physiology
Type
Schools of Medicine
DUNS #
065391526
City
Charlottesville
State
VA
Country
United States
Zip Code
22904
Yang, Sung-Tae; Lim, Sung In; Kiessling, Volker et al. (2016) Site-specific fluorescent labeling to visualize membrane translocation of a myristoyl switch protein. Sci Rep 6:32866
Dawidowski, Damian; Cafiso, David S (2016) Munc18-1 and the Syntaxin-1 N Terminus Regulate Open-Closed States in a t-SNARE Complex. Structure 24:392-400
Milovanovic, Dragomir; Platen, Mitja; Junius, Meike et al. (2016) Calcium Promotes the Formation of Syntaxin 1 Mesoscale Domains through Phosphatidylinositol 4,5-Bisphosphate. J Biol Chem 291:7868-76
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Park, Yongsoo; Seo, Jong Bae; Fraind, Alicia et al. (2015) Synaptotagmin-1 binds to PIP(2)-containing membrane but not to SNAREs at physiological ionic strength. Nat Struct Mol Biol 22:815-23
Kiessling, Volker; Liang, Binyong; Tamm, Lukas K (2015) Reconstituting SNARE-mediated membrane fusion at the single liposome level. Methods Cell Biol 128:339-63
Kiessling, Volker; Yang, Sung-Tae; Tamm, Lukas K (2015) Supported lipid bilayers as models for studying membrane domains. Curr Top Membr 75:1-23
Kreutzberger, Alex J B; Kiessling, Volker; Tamm, Lukas K (2015) High cholesterol obviates a prolonged hemifusion intermediate in fast SNARE-mediated membrane fusion. Biophys J 109:319-29
Milovanovic, Dragomir; Honigmann, Alf; Koike, Seiichi et al. (2015) Hydrophobic mismatch sorts SNARE proteins into distinct membrane domains. Nat Commun 6:5984

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