Developing an understanding of the molecular mechanisms that underlie synaptic communication, and hence form the basis of learning, memory, and sensory perception, stands as one of the central challenges of modern science. In this proposal, the focus is on one large family of neuroreceptors that plays a central role in this process, the ligand-gated ion channels (LGIC). These proteins mediate fast synaptic transmission, and they are the targets of therapeutic approaches to Alzheimer's disease, Parkinson's disease, schizophrenia, stroke, learning and attention deficits, and drug addiction. A major goal of this work is to develop an understanding of the precise chemical interactions that lead to specific and potent drug-receptor interactions, including both drugs of therapeutic value and drugs of abuse. This will be of considerable value in developing new pharmaceuticals with improved selectivities and potencies. Binding of a drug to an LGIC induces a large structural change in the protein that leads to the opening of an ion channel within the protein, a profound signaling event for the cell. This """"""""gating"""""""" process is central to the function of the receptors, and it will be another focus of investigation. LGICs and other neuroreceptors are complex, multisubunit, integral membrane proteins. As such, the powerful tools of structural biology - x-ray crystallography and NMR spectroscopy - are not readily applicable. This work makes use of the in vivo nonsense suppression method for unnatural amino acid incorporation into proteins expressed in living cells. This approach allows almost limitless modification of the receptors. Subtle changes can be made to reveal key binding interactions. More dramatic changes introduce biophysical tools to probe structure and function. When combined with the power of electrophysiology, unnatural amino acid mutagenesis becomes a powerful, broadly applicable tool for unraveling the critical features of these central players in molecular neurobiology.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37NS034407-16
Application #
7848814
Study Section
Bio-Organic and Natural Products Chemistry Study Section (BNP)
Program Officer
Silberberg, Shai D
Project Start
1995-07-01
Project End
2012-01-14
Budget Start
2010-07-01
Budget End
2012-01-14
Support Year
16
Fiscal Year
2010
Total Cost
$410,419
Indirect Cost
Name
California Institute of Technology
Department
Type
Schools of Engineering
DUNS #
009584210
City
Pasadena
State
CA
Country
United States
Zip Code
91125
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Nichols, Weston A; Henderson, Brandon J; Yu, Caroline et al. (2014) Lynx1 shifts ?4?2 nicotinic receptor subunit stoichiometry by affecting assembly in the endoplasmic reticulum. J Biol Chem 289:31423-32
Marotta, Christopher B; Dilworth, Crystal N; Lester, Henry A et al. (2014) Probing the non-canonical interface for agonist interaction with an ?5 containing nicotinic acetylcholine receptor. Neuropharmacology 77:342-9
Marotta, Christopher B; Rreza, Iva; Lester, Henry A et al. (2014) Selective ligand behaviors provide new insights into agonist activation of nicotinic acetylcholine receptors. ACS Chem Biol 9:1153-9

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