The goal of this research is to characterize the molecular mechanism of acetylcholine receptor function including: 1) the binding of specific ligands, 2) the coupling between ligand binding and ion permeability, 3) the ion permeation mechanism and 4) desensitization, a process in which ion permeability is blocked in the prolonged presence of activating ligands. The emphasis in this project is on membrane interactions that are important in the regulation of the above processes. Spectroscopic techniques, such as electron paramagnetic resonance and fluorescence, will be used to provide detailed information about lipid and protein dynamics and lipid-protein interactions. Most experiments will be carried out on both native and reconstituted membrane vesicles prepared from the electric tissue of the electric ray Torpedo californica. Ion fluxes will be measured on the millesecond time scale using rapid kinetics techniques. The acetylcholine receptor is an essential component in synaptic transmission and the experiments will provide detailed information about normal nerve and muscle interactions. In addition, the acetylcholine receptor is one of the few integral membrane proteins that can be studied in biochemical detail at many different levels of cellular organization. Thus the membrane phenomena important for this receptor may also be important for other receptor systems in the central nervous system that are more difficult to analyze.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS013050-14
Application #
3395083
Study Section
Biophysics and Biophysical Chemistry B Study Section (BBCB)
Project Start
1979-05-01
Project End
1994-04-30
Budget Start
1989-05-01
Budget End
1990-04-30
Support Year
14
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of California Davis
Department
Type
Earth Sciences/Resources
DUNS #
094878337
City
Davis
State
CA
Country
United States
Zip Code
95618
Ortiz-Miranda, S I; Lasalde, J A; Pappone, P A et al. (1997) Mutations in the M4 domain of the Torpedo californica nicotinic acetylcholine receptor alter channel opening and closing. J Membr Biol 158:17-30
Bhushan, A; McNamee, M G (1993) Correlation of phospholipid structure with functional effects on the nicotinic acetylcholine receptor. A modulatory role for phosphatidic acid. Biophys J 64:716-23
Narayanaswami, V; Kim, J; McNamee, M G (1993) Protein-lipid interactions and Torpedo californica nicotinic acetylcholine receptor function. 1. Spatial disposition of cysteine residues in the gamma subunit analyzed by fluorescence-quenching and energy-transfer measurements. Biochemistry 32:12413-9
Narayanaswami, V; McNamee, M G (1993) Protein-lipid interactions and Torpedo californica nicotinic acetylcholine receptor function. 2. Membrane fluidity and ligand-mediated alteration in the accessibility of gamma subunit cysteine residues to cholesterol. Biochemistry 32:12420-7
Sunshine, C; McNamee, M G (1992) Lipid modulation of nicotinic acetylcholine receptor function: the role of neutral and negatively charged lipids. Biochim Biophys Acta 1108:240-6
Chattopadhyay, A; McNamee, M G (1991) Average membrane penetration depth of tryptophan residues of the nicotinic acetylcholine receptor by the parallax method. Biochemistry 30:7159-64
Ochoa, E L; Li, L A; Plummer, A et al. (1990) Direct effects of thymopentin (Arg-Lys-Asp-Val-Tyr) on cholinergic agonist-induced slow inactivation of nicotinic acetylcholine receptor function. Mol Pharmacol 38:863-71
Bhushan, A; McNamee, M G (1990) Differential scanning calorimetry and Fourier transform infrared analysis of lipid-protein interactions involving the nicotinic acetylcholine receptor. Biochim Biophys Acta 1027:93-101
Jones, O T; McNamee, M G (1988) Annular and nonannular binding sites for cholesterol associated with the nicotinic acetylcholine receptor. Biochemistry 27:2364-74
Jones, O T; Eubanks, J H; Earnest, J P et al. (1988) A minimum number of lipids are required to support the functional properties of the nicotinic acetylcholine receptor. Biochemistry 27:3733-42

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