: Synaptic transmission in brain is initiated by neurotransmitter release, which is mediated by synaptic vesicle exocytosis. Insight into the mechanisms of neurotransmitter release is essential for understanding how the brain processes information, and how synaptic transmission is affected in diseases such as Parkinson's disease, Alzheimer's disease, and drug addiction. Syntaxin is a SNARE protein on the presynaptic plasma membrane that is essential for neurotransmitter release. Syntaxin 1 functions at the membrane fusion step in exocytosis by interacting with a number of target proteins, but its precise mechanism of action remains incompletely understood. In the current application we propose a series of interdisciplinary experiments to examine the precise functions of syntaxin 1 in neurotransmitter release, and to relate this function to the role of other syntaxins in other membrane fusion processes. The proposed experiments unite structural and biophysical studies that combine multidimensional NMR techniques, biochemical approaches, and in vivo methods using PC12 cells and transgenic mice to achieve a comprehensive understanding of syntaxin 1 function.
Five specific aims are proposed: (1) To determine the structure at atomic resolution of the """"""""closed conformation"""""""" of syntaxin 1 and to study its conservation in other mammalian syntaxins. (2) To determine the structural basis for the interaction between syntaxin 1 and munc13-1, and to study the potential role of munc13-1 in promoting the conformational switch of syntaxin 1. (3) To determine the mode of binding of complexins to the core complex, and to study the consequences of this interaction on the properties of the core complex. (4) To study the in vivo function of syntaxin 1 in mice using transgenic and gene targeting methods. (5) To perform a systematic analysis of the structural properties of yeast syntaxins and of their interactions with proteins of the secl/muncl8 family. The results of this research will not only be important to understand the mechanisms of neurotransmitter release and membrane fusion in general, but will also have an impact in the design of therapies for brain disorders that involve changes in synaptic transmission.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS037200-09
Application #
7039031
Study Section
Special Emphasis Panel (ZRG1-SSS-P (01))
Program Officer
Talley, Edmund M
Project Start
1997-12-01
Project End
2007-04-30
Budget Start
2006-04-01
Budget End
2007-04-30
Support Year
9
Fiscal Year
2006
Total Cost
$325,614
Indirect Cost
Name
University of Texas Sw Medical Center Dallas
Department
Biochemistry
Type
Schools of Medicine
DUNS #
800771545
City
Dallas
State
TX
Country
United States
Zip Code
75390
Xu, Junjie; Camacho, Marcial; Xu, Yibin et al. (2017) Mechanistic insights into neurotransmitter release and presynaptic plasticity from the crystal structure of Munc13-1 C1C2BMUN. Elife 6:
Park, Seungmee; Bin, Na-Ryum; Yu, Bin et al. (2017) UNC-18 and Tomosyn Antagonistically Control Synaptic Vesicle Priming Downstream of UNC-13 in Caenorhabditis elegans. J Neurosci 37:8797-8815
Sitarska, Ewa; Xu, Junjie; Park, Seungmee et al. (2017) Autoinhibition of Munc18-1 modulates synaptobrevin binding and helps to enable Munc13-dependent regulation of membrane fusion. Elife 6:
Liu, Xiaoxia; Seven, Alpay Burak; Xu, Junjie et al. (2017) Simultaneous lipid and content mixing assays for in vitro reconstitution studies of synaptic vesicle fusion. Nat Protoc 12:2014-2028
Voleti, Rashmi; Tomchick, Diana R; Südhof, Thomas C et al. (2017) Exceptionally tight membrane-binding may explain the key role of the synaptotagmin-7 C2A domain in asynchronous neurotransmitter release. Proc Natl Acad Sci U S A 114:E8518-E8527
Pan, Yun-Zu; Quade, Bradley; Brewer, Kyle D et al. (2016) Sequence-specific assignment of methyl groups from the neuronal SNARE complex using lanthanide-induced pseudocontact shifts. J Biomol NMR 66:281-293
Liu, Xiaoxia; Seven, Alpay Burak; Camacho, Marcial et al. (2016) Functional synergy between the Munc13 C-terminal C1 and C2 domains. Elife 5:
Yang, Xiaoyu; Wang, Shen; Sheng, Yi et al. (2015) Syntaxin opening by the MUN domain underlies the function of Munc13 in synaptic-vesicle priming. Nat Struct Mol Biol 22:547-54
Rizo, Josep; Xu, Junjie (2015) The Synaptic Vesicle Release Machinery. Annu Rev Biophys 44:339-67
Trimbuch, Thorsten; Xu, Junjie; Flaherty, David et al. (2014) Re-examining how complexin inhibits neurotransmitter release. Elife 3:e02391

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