Date of Award

1-1-2018

Language

English

Document Type

Master's Thesis

Degree Name

Master of Science (MS)

College/School/Department

Department of Chemistry

Content Description

1 online resource (ii, v, 52 pages) : illustrations (some color)

Dissertation/Thesis Chair

Li Niu

Keywords

AMPA, GluA2, GluA3, Ion channels, Glutamic acid, Neurotransmitter receptors, RNA splicing, Messenger RNA

Subject Categories

Biochemistry | Neuroscience and Neurobiology

Abstract

Prior studies of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, including that of GluA3 AMPA receptor subunit, have shown that alternative mRNA splicing, which generates flip and flop variants with different amino acid sequences, gives rise to functional differences between the two variants. The goal of this MS thesis is to investigate the basic gating properties of the heteromeric complex channels formed from GluA2R/GluA3 AMPA receptor subunits and the different variants between the two subunits. The hypothesis to be tested is whether different GluA3 variants affect the channel gating properties when each of the variants is in a complex with the Q/R-site edited isoform of the GluA2 AMPA receptor GluA2R subunit. Using laser-pulse photolysis technique and whole-cell recording, I characterized the rate of channel opening and closing of two alternatively spliced variants of a complex channel formed with GluA3: i.e., GluA2Rflip/3flip & GluA2Rflip/3flop. I show that change of the GluA3 alternative splicing status in the channel complex affects the rate of channel opening, but not the rate at channel closing, nor the binding affinity for glutamate. Explicitly, the GluA3 flop variant, when complexed with GluA2Rflip opens its channel roughly 2-fold faster, compared with the complex containing the GluA3flip variant. Furthermore, I show that GluA3 did not form a functional channel with the GluA2Rflop subunit with appreciable whole-cell current response.

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