Our long-term goal is to understand how rapidly-activated synaptic receptors convert a chemical signal into an electrical one, and how disease and therapeutic drugs alter this process. The process of chemo-electrical transduction is fundamental to the proper functioning of the nervous system, yet its mechanistic and structural bases are poorly understood. Toward understanding chemo-electrical transduction, the proposed studies will determine how the neurotransmitter acetylcholine (ACh) activates ACh receptors (AChRs) from voluntary skeletal muscle and alpha7 AChRs from neurons and cells of the inflammatory system. In particular, we will address major gaps in understanding the activation mechanism through a combination of high resolution single channel recording, kinetic analyses and structural perturbations. First, we will define elementary reaction steps that underlie AChR activation, and then identify structures that mediate each reaction step. Second, we will delineate structural and mechanistic bases of agonist efficacy. Third, we will define structural underpinnings of cooperativity in AChR activation. Completion of this project will yield both mechanistic and structural understanding of chemo-electrical transduction applicable to therapeutic drug design and treatment of neurological diseases including muscle weakness disorders, Parkinson's and Alzheimer's diseases and schizophrenia.

Public Health Relevance

Nicotinic acetylcholine receptors (AChRs) mediate cell-cell communication throughout the nervous system, and are associated with a broad spectrum of neurological diseases, including congenital myasthenic syndromes, epilepsy, Alzheimer's and Parkinson's diseases, schizophrenia and nicotine addiction. This project will delineate mechanisms of chemo-electrical transduction by AChRs from skeletal muscle, given their central role in neuromuscular disease, and by alpha 7 AChRs from neurons and cells of the inflammatory system, given their relevance to psychiatric and neurodegenerative diseases. The resulting mechanistic understanding will enable rational treatment of neurological diseases and form bases to develop therapeutic drugs.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS031744-23
Application #
8877633
Study Section
Biophysics of Neural Systems Study Section (BPNS)
Program Officer
Silberberg, Shai D
Project Start
1992-09-01
Project End
2018-04-30
Budget Start
2015-05-01
Budget End
2016-04-30
Support Year
23
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Mayo Clinic, Rochester
Department
Type
DUNS #
006471700
City
Rochester
State
MN
Country
United States
Zip Code
55905
Shen, Xin-Ming; Brengman, Joan M; Shen, Shelley et al. (2018) Mutations causing congenital myasthenia reveal principal coupling pathway in the acetylcholine receptor ?-subunit. JCI Insight 3:
Bouzat, Cecilia; Sine, Steven M (2018) Nicotinic acetylcholine receptors at the single-channel level. Br J Pharmacol 175:1789-1804
Mukhtasimova, Nuriya; Sine, Steven M (2018) Full and partial agonists evoke distinct structural changes in opening the muscle acetylcholine receptor channel. J Gen Physiol 150:713-729
Mazzaferro, Simone; Bermudez, Isabel; Sine, Steven M (2017) ?4?2 Nicotinic Acetylcholine Receptors: RELATIONSHIPS BETWEEN SUBUNIT STOICHIOMETRY AND FUNCTION AT THE SINGLE CHANNEL LEVEL. J Biol Chem 292:2729-2740
Mukhtasimova, Nuriya; daCosta, Corrie J B; Sine, Steven M (2016) Improved resolution of single channel dwell times reveals mechanisms of binding, priming, and gating in muscle AChR. J Gen Physiol 148:43-63
Shen, Xin-Ming; Brengman, Joan; Neubauer, David et al. (2016) Investigation of Congenital Myasthenia Reveals Functional Asymmetry of Invariant Acetylcholine Receptor (AChR) Cys-loop Aspartates. J Biol Chem 291:3291-301
daCosta, Corrie J B; Free, Chris R; Sine, Steven M (2015) Stoichiometry for ?-bungarotoxin block of ?7 acetylcholine receptors. Nat Commun 6:8057
Engel, Andrew G; Shen, Xin-Ming; Selcen, Duygu et al. (2015) Congenital myasthenic syndromes: pathogenesis, diagnosis, and treatment. Lancet Neurol 14:420-34
Sine, Steven M; Huang, Sun; Li, Shu-Xing et al. (2013) Inter-residue coupling contributes to high-affinity subtype-selective binding of ?-bungarotoxin to nicotinic receptors. Biochem J 454:311-21
Huang, Sun; Li, Shu-Xing; Bren, Nina et al. (2013) Complex between ?-bungarotoxin and an ?7 nicotinic receptor ligand-binding domain chimaera. Biochem J 454:303-310

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