2024-03-28T08:51:09Zhttps://keep.lib.asu.edu/oai/requestoai:keep.lib.asu.edu:node-1351532021-08-11T21:09:57Zoai_pmh:all135153
https://hdl.handle.net/2286/R.I.38820
http://rightsstatements.org/vocab/InC/1.0/
2016-05
39 pages
eng
Sepich, Caraline
Barrett, The Honors College
Text
Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels expressed in the central nervous system, peripheral nervous system, and at nerve-muscle junctions which open upon the binding of acetylcholine or nicotine to allow positive ions to flow across the cell membrane. A subset of nAChRs which contain the α6 subunit (α6*-nAChRs) are particularly unique in their restricted expression to the visual system and the catecholaminergic pathways, which are associated with addiction and movement control, as well as in their difficulty to express in cell lines or Xenopus oocytes for laboratory study. In this project, several human α6/α3 chimeras and α6 mutants were designed to test the structural basis of membrane trafficking, single-channel conductance, and ethanol regulation of α6*-nAChRs. These constructs were coexpressed in Xenopus oocytes with human β2 and β3 subunits, and their function was tested by two-electrode voltage clamp electrophysiological recordings. The data indicates that, though null mutation of potential arginine-based endoplasmic reticulum (ER) retention sequences did not enhance channel expression, mutation of potential phosphorylation sites to contain negative charges may have enhanced expression and a mutation to potentially enhance single channel conductance also led to increased current in expressed channels. Further, α6/α3 chimeras appear to be possibly potentiated by ethanol as an allosteric regulator but inhibited by ethanol at high concentrations. The structure of these chimeras also indicates that ethanol binding site(s) are likely in the N-terminal and possibly transmembrane domains. These findings not only provide insight about the structural basis of ethanol regulation and expression of α6*-nAChRs, they provide a starting point for creating new methods of expression and new chemical modulators of these channels which will aid in further research. Ultimately, this could lead to a better understanding of the pathophysiology of addiction and movement disorders and pave the way for new treatments.
Investigating the Expression of Zinc-Activated Cation Channel (ZCAN) in Immune Cells