Abstract

There is limited knowledge about the relationship between the GABAA receptor subunit composition and the synaptic, extrasynaptic and other subcellular localization of this receptor. This is in spite of the importance of the GABAA receptor in brain function. It has been estimated that 40% of the brain synapses are GABAergic. The long-term objective of this proposal is to understand the molecular mechanisms involved in clustering and anchoring GABAA receptors at the postsynaptic membrane.
The aims of this proposal are: 1) To identify the amino acids of various subunits involved in the synaptic clustering of the GABAA receptors; 2) To study the synaptic and extrasynaptic localization of the gamma 3 and alpha 5 subunits and 3) To biochemically separate and characterize synaptic and non-synaptic GABAA receptors from various subcellular fractions isolated from the brain. Already available subunit-specific GABAA receptor antibodies in combination with immunocytochemistry at the light microscopy and electron microscopy levels will be used for revealing the cellular, subcellular and synaptic localization of various GABAA receptors in the rat brain and in hippocampal cultures. The same antibodies will be used for the biochemical characterization of the GABAA receptors in the subcellular fractions isolated from the brain. Techniques such as siRNA treatment of cultured hippocampal neurons and the expression of mutated GABAA receptor subunits in these cultures and in the brain will also be used aiming to elucidate the mechanisms involved in the synaptic clustering of GABAA receptors. These studies are relevant for understanding the mechanisms involved in the formation, maintenance and plasticity of the inhibitory GABAergic synapses in the brain. It is predicted that the inappropriate synaptic and extrasynaptic localization of GABAA receptors affects GABAergic synaptic function and brain development, leading to neurological and mental disorders. These studies will also be relevant for designing GABAergic therapeutic drugs with higher clinical specificity and fewer side effects.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS039287-07
Application #
7173410
Study Section
Neurotransporters, Receptors, and Calcium Signaling Study Section (NTRC)
Program Officer
Silberberg, Shai D
Project Start
1999-12-01
Project End
2009-01-31
Budget Start
2007-02-01
Budget End
2008-01-31
Support Year
7
Fiscal Year
2007
Total Cost
$323,761
Indirect Cost

  Institution

Name
University of Connecticut
Department
Physiology
Type
Schools of Arts and Sciences
DUNS #
614209054
City
Storrs-Mansfield
State
CT
Country
United States
Zip Code
06269

  Publications

Frykman, Susanne; Hur, Ji-Yeun; Franberg, Jenny et al. (2010) Synaptic and endosomal localization of active gamma-secretase in rat brain. PLoS One 5:e8948
Li, Yanfang; Serwanski, David R; Miralles, Celia P et al. (2010) Synaptic and nonsynaptic localization of protocadherin-gammaC5 in the rat brain. J Comp Neurol 518:3439-63
Li, Xuejing; Serwanski, David R; Miralles, Celia P et al. (2009) Septin 11 is present in GABAergic synapses and plays a functional role in the cytoarchitecture of neurons and GABAergic synaptic connectivity. J Biol Chem 284:17253-65
Yu, Wendou; De Blas, Angel L (2008) Gephyrin expression and clustering affects the size of glutamatergic synaptic contacts. J Neurochem 104:830-45
Li, Xuejing; Serwanski, David R; Miralles, Celia P et al. (2007) Two pools of Triton X-100-insoluble GABA(A) receptors are present in the brain, one associated to lipid rafts and another one to the post-synaptic GABAergic complex. J Neurochem 102:1329-45
Yu, Wendou; Jiang, Min; Miralles, Celia P et al. (2007) Gephyrin clustering is required for the stability of GABAergic synapses. Mol Cell Neurosci 36:484-500
Serwanski, David R; Miralles, Celia P; Christie, Sean B et al. (2006) Synaptic and nonsynaptic localization of GABAA receptors containing the alpha5 subunit in the rat brain. J Comp Neurol 499:458-70
Charych, Erik I; Li, Rongwen; Serwanski, David R et al. (2006) Identification and characterization of two novel splice forms of GRIP1 in the rat brain. J Neurochem 97:884-98
Christie, S B; Li, R-W; Miralles, C P et al. (2006) Clustered and non-clustered GABAA receptors in cultured hippocampal neurons. Mol Cell Neurosci 31:1-14
Li, Rong-Wen; Serwanski, David R; Miralles, Celia P et al. (2005) GRIP1 in GABAergic synapses. J Comp Neurol 488:11-27

Showing the most recent 10 out of 18 publications