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" Investigating the Physiological Role of Chloride Permeation through Excitatory Amino Acid Transporter 1 (EAAT1) "
Akhter, Muhammad Azman
van Meyel, Don
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Latin Dissertation
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| Language of Document
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English
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| Record Number
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1058893
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| Doc. No
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TL58010
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| Main Entry
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Akhter, Muhammad Azman
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| Title & Author
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Investigating the Physiological Role of Chloride Permeation through Excitatory Amino Acid Transporter 1 (EAAT1)\ Akhter, Muhammad Azmanvan Meyel, Don
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| College
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McGill University (Canada)
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| Date
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2019
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| Degree
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M.Sc.
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2019
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| Note
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68 p.
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| Abstract
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Astrocytes maintain ion and neurotransmitter homeostasis within the central nervous system. They do so by expressing channels, receptors and transporters such as excitatory amino acid transporters (EAATs) along their highly ramified arbours. EAATs are well known to be glutamate transporters, but they have a dual function as chloride channels. The conservation of the EAAT anion channel from GltPh in prokaryotes to mammals suggests an essential physiological role. However, few studies have addressed the role of chloride permeation through EAAT1 in vivo, so its importance for normal brain function is not yet completely understood. During my project, I built tools to separate the chloride channel and glutamate transport functions of the human EAAT1 (hEAAT1) protein. Through an extensive literature review, I identified a series of hEAAT1 mutations that only affect the permeation and gating properties of the Cl- channel, without affecting glutamate transport function. I built transgenic flies where these altered hEAAT1 proteins were expressed in Drosophila astrocytes in vivo. Additionally, I built transgenic flies to investigate the contribution of hEAAT1 Cl- channel in the cytopathology of Episodic Ataxia Type 6 using five new patient-derived mutations. Using an antibody to hEAAT1, I first validated the expression and proper localization of these altered hEAAT1 proteins within glial cells. Additionally, I developed an improved and optimized method to quantify the crawling behaviour of L1 larvae. With this locomotion assay, I showed that EAAT1 is required in astrocytes for motor behavior, and that ensheathing glia provide an EAAT1-mediated function that is essential for animal survival. Using these transgenic flies coupled with the new locomotion assay, our lab is poised to determine the physiological role of hEAAT1 Cl- channel in glial cells. Our preliminary data provide the first direct evidence that the hEAAT1 Cl- channel is essential for its function in glial cells in vivo under physiological conditions.
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| Descriptor
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Amino acids
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Chloride
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Graduate students
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Homeostasis
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Insects
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Mammals
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Mutation
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Nervous system
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Physiology
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van Meyel, Don
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McGill University (Canada)
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