Glutamate transporters remove glutamate from synapses to maintain an efficient synaptic communication between neurons and to prevent extracellular glutamate concentrations from reaching neuro-toxic levels. The long-term goal of this project is to understand the molecular mechanism of glutamate transporter. It is important to understand the molecular mechanism by which glutamate transporters achieved glutamate uptake, because this will lead to a better understanding of synaptic communication in the brain, as well as, lead to treatments to prevent neuronal death due to glutamate toxicity during, for example, ischemia. In addition, this study will provide essential structural and dynamical information about the glutamate transporters, an area of research in which there are only a few numbers of groups working. Our current knowledge of the structure and function of glutamate transporters is very limited. No structural model has yet been suggested that can explain how glutamate transporters accomplish glutamate uptake. We propose to use fluorescence and biochemical methods to elucidate the structure and function of glutamate transporters, using fluorescent and non-fluorescent cysteine reactive probes. These techniques allow us to obtain structural as well as dynamical information about the molecular mechanism of glutamate transporters. Our objective is to construct a structural model of glutamate transporters and to elucidate how changes in this structure lead to glutamate transport.
The aims of the proposed project are: 1) To identify the domains of the glutamate transporters that undergo conformational changes during the transport cycle; and 2) To identify residues that undergo alternating access during glutamate transport.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS051169-01A1
Application #
6924506
Study Section
Special Emphasis Panel (ZRG1-MDCN-A (05))
Program Officer
Silberberg, Shai D
Project Start
2005-03-01
Project End
2009-02-28
Budget Start
2005-03-01
Budget End
2006-02-28
Support Year
1
Fiscal Year
2005
Total Cost
$297,088
Indirect Cost
Name
Oregon Health and Science University
Department
Type
Schools of Medicine
DUNS #
096997515
City
Portland
State
OR
Country
United States
Zip Code
97239
Zhou, Yun; Wang, Xiaoyu; Tzingounis, Anastasios V et al. (2014) EAAT2 (GLT-1; slc1a2) glutamate transporters reconstituted in liposomes argues against heteroexchange being substantially faster than net uptake. J Neurosci 34:13472-85
Focke, Paul J; Wang, Xiaoyu; Larsson, H Peter (2013) Neurotransmitter transporters: structure meets function. Structure 21:694-705
Focke, Paul J; Moenne-Loccoz, Pierre; Larsson, H Peter (2011) Opposite movement of the external gate of a glutamate transporter homolog upon binding cotransported sodium compared with substrate. J Neurosci 31:6255-62
Larsson, H Peter; Wang, Xiaoyu; Lev, Bogdan et al. (2010) Evidence for a third sodium-binding site in glutamate transporters suggests an ion/substrate coupling model. Proc Natl Acad Sci U S A 107:13912-7
Gonzalez, Carlos; Koch, Hans P; Drum, Ben M et al. (2010) Strong cooperativity between subunits in voltage-gated proton channels. Nat Struct Mol Biol 17:51-6
Gonzalez, Carlos; Larsson, H Peter (2010) Permeation mechanism in voltage-activated proton channels: a new glimpse. Proc Natl Acad Sci U S A 107:1817-8
Ortiz, Diana; Sanchez, Marco A; Koch, Hans P et al. (2009) An acid-activated nucleobase transporter from Leishmania major. J Biol Chem 284:16164-9
Vemana, Sriharsha; Pandey, Shilpi; Larsson, H Peter (2008) Intracellular Mg2+ is a voltage-dependent pore blocker of HCN channels. Am J Physiol Cell Physiol 295:C557-65
Koch, Hans Peter; Brown, Ronald Lane; Larsson, Hans Peter (2007) The glutamate-activated anion conductance in excitatory amino acid transporters is gated independently by the individual subunits. J Neurosci 27:2943-7
Koch, Hans P; Hubbard, Jeffrey M; Larsson, H Peter (2007) Voltage-independent sodium-binding events reported by the 4B-4C loop in the human glutamate transporter excitatory amino acid transporter 3. J Biol Chem 282:24547-53

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