Glutamate is the primary excitatory neurotransmitter of the vertebrate CNS and the Drosophila neuromuscular junction (NMJ). The vesicular glutamate transporter (VGLUT) is responsible for filling synaptic vesicles with transmitter at glutamatergic synapses. The glutamate content of a synaptic vesicle is a fundamental parameter controlling the strength of synaptic transmission in the healthy brain, while the misregulated release of vesicular glutamate may contribute to the pathophysiology of such diseases as stroke, ALS, and epilepsy. This proposal will test the hypothesis that the expression, trafficking, and activity of the Drosophila homolog of VGLUT (D VGLUT) regulates the function, plasticity, and development of a glutamatergic synapse by controlling the glutamate content of synaptic vesicles. Our studies will combine genetic, cell biological, and electrophysiological methods to test the function of this important protein. The Drosophila homolog of the vesicular glutamate transporter (DVGLUT) has been identified and mutants have been generated that allow for the manipulation of its expression at the synapse. Biochemical, electrophysiological, and electron microscopic techniques will be employed to investigate the physiological role of DVGLUT in the filling of synaptic vesicles with glutamate (Aim 1). Neurotransmitter not only mediates synaptic transmission, but can also regulate the development of synapses. DVGLUT mutants will be used to manipulate the levels of glutamate in synaptic vesicles and the consequences for synapse formation, glutamate receptor localization, and synaptic maturation will be investigated (Aim 2). Finally, the mechanisms regulating the membrane trafficking of DVGLUT will be determined in order to define the role of DVGLUT trafficking in the regulation of glutamatergic transmission (Aim 3). The results of these experiments will provide novel and fundamental information on the mechanisms by which VGLUT contributes to the development and function of glutamatergic synapses.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS051453-01
Application #
6907686
Study Section
Synapses, Cytoskeleton and Trafficking Study Section (SYN)
Program Officer
Talley, Edmund M
Project Start
2005-04-01
Project End
2009-03-31
Budget Start
2005-04-01
Budget End
2006-03-31
Support Year
1
Fiscal Year
2005
Total Cost
$317,044
Indirect Cost
Name
Washington University
Department
Other Basic Sciences
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Daniels, Richard W; Miller, Bradley R; DiAntonio, Aaron (2011) Increased vesicular glutamate transporter expression causes excitotoxic neurodegeneration. Neurobiol Dis 41:415-20
Grygoruk, Anna; Fei, Hao; Daniels, Richard W et al. (2010) A tyrosine-based motif localizes a Drosophila vesicular transporter to synaptic vesicles in vivo. J Biol Chem 285:6867-78
Simon, Anne F; Daniels, Richard; Romero-Calderón, Rafael et al. (2009) Drosophila vesicular monoamine transporter mutants can adapt to reduced or eliminated vesicular stores of dopamine and serotonin. Genetics 181:525-41
Fei, Hao; Grygoruk, Anna; Brooks, Elizabeth S et al. (2008) Trafficking of vesicular neurotransmitter transporters. Traffic 9:1425-36
Daniels, Richard W; Gelfand, Maria V; Collins, Catherine A et al. (2008) Visualizing glutamatergic cell bodies and synapses in Drosophila larval and adult CNS. J Comp Neurol 508:131-52
Romero-Calderon, Rafael; Shome, Ratula M; Simon, Anne F et al. (2007) A screen for neurotransmitter transporters expressed in the visual system of Drosophila melanogaster identifies three novel genes. Dev Neurobiol 67:550-69
Collins, Catherine A; DiAntonio, Aaron (2007) Synaptic development: insights from Drosophila. Curr Opin Neurobiol 17:35-42