Abstract
The Na+-dependent glutamate transporter EAAT3 facilitates glutamate uptake into neurons as well as many other cell types. GTRAP3-18 (JWA, Arl6ip5) is a novel protein that interacts with EAAT3 and negatively modulates EAAT3-mediated glutamate uptake. Previous studies suggest that retinoic acid (RA) decreases Na+-dependent glutamate uptake and increases GTRAP3-18 protein expression. However, the RA used in those studies was complexed with methyl-beta-cyclodextrin (MebetaCD). In the present study we found that MebetaCD, but not RA, significantly reduced Na+-dependent EAAT3-mediated [3H]glutamate uptake in human embryonic kidney 293 (HEK293) cells. MebetaCD also significantly increased GTRAP3-18 protein expression in HEK293 cells as well as in rat hypothalamic neuron cultures. Intracerebroventricular administration of MebetaCD to the mouse brain resulted in a significant increase in GTRAP3-18 immunoreactivity in the hippocampus and cerebral cortex. In conclusion, we have shown that MebetaCD reduces EAAT3-mediated glutamate uptake and induces the expression of GTRAP3-18 protein.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Transport System X-AG / metabolism*
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Animals
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Carrier Proteins / metabolism*
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Cell Line
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Cells, Cultured
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Cerebral Cortex / drug effects
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Cerebral Cortex / metabolism
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Cyclodextrins / administration & dosage
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Cyclodextrins / pharmacology*
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Excitatory Amino Acid Transporter 3
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Glutamate Plasma Membrane Transport Proteins
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Glutamic Acid / pharmacokinetics*
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Heat-Shock Proteins
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Hippocampus / drug effects
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Hippocampus / metabolism
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Humans
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Hypothalamus / cytology
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Injections, Intraventricular
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Kidney / cytology
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Kidney / drug effects
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Kidney / metabolism
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Male
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Membrane Transport Proteins
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Mice
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Mice, Inbred C57BL
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Neurons / cytology
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Neurons / drug effects
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Neurons / metabolism
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Sodium / metabolism
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Symporters / metabolism*
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Tretinoin / pharmacology*
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beta-Cyclodextrins*
Substances
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Amino Acid Transport System X-AG
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Arl6ip5 protein, mouse
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Carrier Proteins
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Cyclodextrins
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Excitatory Amino Acid Transporter 3
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Glutamate Plasma Membrane Transport Proteins
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Heat-Shock Proteins
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Membrane Transport Proteins
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SLC1A1 protein, human
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Slc1a1 protein, mouse
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Symporters
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beta-Cyclodextrins
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methyl-beta-cyclodextrin
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Glutamic Acid
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Tretinoin
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Sodium