Abstract
To localize functionally significant domains in the amino acid transporters of mouse brain mEAAC1 and mASCT1, cRNA encoding for wild-type and chimeric transporters was injected into Xenopus oocytes. Activity of expressed transporters was investigated by measurements of uptake of 3H-labeled glutamate and serine and of glutamate- and serine-induced currents under voltage clamp. Though all transporters accept glutamate and serine as substrate, the central part of the protein (Ala94-Met418 of mEAAC1 and Ala119-Ile393 of mASCT1) determines substrate selectivity. The C-terminus rectifies the interaction with the respective substrate. A channel mode of the glutamate transporter can be activated by glutamate and serine, and the N- and C-termini of the mEAAC1 seem to be essential for the channel formation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Amino Acid Transport System X-AG*
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Amino Acid Transport Systems
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Amino Acids / metabolism*
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Animals
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Base Sequence
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Biological Transport, Active
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Carrier Proteins / chemistry*
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Carrier Proteins / genetics
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Carrier Proteins / metabolism*
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DNA Primers / genetics
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Excitatory Amino Acid Transporter 3
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Female
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Glutamate Plasma Membrane Transport Proteins
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Glutamic Acid / metabolism
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In Vitro Techniques
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Mice
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Molecular Sequence Data
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Oocytes / metabolism
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Protein Structure, Tertiary
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Sequence Homology, Amino Acid
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Serine / metabolism
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Symporters*
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Xenopus laevis
Substances
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Amino Acid Transport System X-AG
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Amino Acid Transport Systems
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Amino Acids
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Carrier Proteins
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DNA Primers
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Excitatory Amino Acid Transporter 3
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Glutamate Plasma Membrane Transport Proteins
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Recombinant Fusion Proteins
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Slc1a1 protein, mouse
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Symporters
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Glutamic Acid
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Serine