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rdf:type |
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lifeskim:mentions |
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pubmed:dateCreated |
1997-2-27
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pubmed:abstractText |
1. The interaction of L-cysteine with three excitatory amino acid transporter subtypes cloned from human brain (EAAT1-3) was examined by measuring transporter-mediated electrical currents and radiolabelled amino acid flux in voltage-clamped Xenopus oocytes expressing the transporters. 2. L-Cysteine was transported by the neuronal subtype EAAT3 (EAAC1) with an affinity constant of 190 microM and a maximal rate of flux similar to that of L-glutamate; the relative efficacies (Vmax/K(m)) of the EAAT1 and EAAT2 subtypes for transporting L-cysteine were 10- to 20-fold lower. 3. Changing the ionization state of L-cysteine by raising the external pH did not significantly change the apparent affinity, transport rate, or magnitude of currents induced by L-cysteine, suggesting that both the neutral zwitterionic and anionic forms of the amino acid are transported with the same net charge stoichiometry. 4. In addition to competing with L-glutamate for uptake by the neuronal carrier, L-cysteine caused transporter-mediated release of transmitter by heteroexchange; both actions would elevate extracellular glutamate concentrations and may thus contribute to the known excitotoxic actions of L-cysteine in the brain. 5. Because the EAAT3 transporter is also expressed in tissues including kidney and intestine, the results suggest the possibility of a heretofore unrecognized mechanism of L-cysteine uptake in peripheral tissues as well as in brain.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-14024354,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-1448171,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-1688033,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-1859531,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-1980041,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-2185543,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-2725827,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-5075344,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-5464249,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-6140027,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-7478939,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-7546750,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-7903894,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-7917301,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8782106-8495346
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Alanine,
http://linkedlifedata.com/resource/pubmed/chemical/Amino Acid Transport System X-AG,
http://linkedlifedata.com/resource/pubmed/chemical/Carrier Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Cysteine,
http://linkedlifedata.com/resource/pubmed/chemical/Excitatory Amino Acid Transporter 1,
http://linkedlifedata.com/resource/pubmed/chemical/Excitatory Amino Acid Transporter 2,
http://linkedlifedata.com/resource/pubmed/chemical/Excitatory Amino Acid Transporter 3,
http://linkedlifedata.com/resource/pubmed/chemical/Glutamate Plasma Membrane...,
http://linkedlifedata.com/resource/pubmed/chemical/Glutamic Acid,
http://linkedlifedata.com/resource/pubmed/chemical/Protons,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Neurotransmitter,
http://linkedlifedata.com/resource/pubmed/chemical/SLC1A1 protein, human,
http://linkedlifedata.com/resource/pubmed/chemical/SLC1A3 protein, human,
http://linkedlifedata.com/resource/pubmed/chemical/Symporters
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pubmed:status |
MEDLINE
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pubmed:month |
Jun
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pubmed:issn |
0022-3751
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
1
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pubmed:volume |
493 ( Pt 2)
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
419-23
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:8782106-Alanine,
pubmed-meshheading:8782106-Amino Acid Transport System X-AG,
pubmed-meshheading:8782106-Animals,
pubmed-meshheading:8782106-Binding, Competitive,
pubmed-meshheading:8782106-Biological Transport, Active,
pubmed-meshheading:8782106-Brain Chemistry,
pubmed-meshheading:8782106-Carrier Proteins,
pubmed-meshheading:8782106-Cysteine,
pubmed-meshheading:8782106-Electrophysiology,
pubmed-meshheading:8782106-Excitatory Amino Acid Transporter 1,
pubmed-meshheading:8782106-Excitatory Amino Acid Transporter 2,
pubmed-meshheading:8782106-Excitatory Amino Acid Transporter 3,
pubmed-meshheading:8782106-Glutamate Plasma Membrane Transport Proteins,
pubmed-meshheading:8782106-Glutamic Acid,
pubmed-meshheading:8782106-Humans,
pubmed-meshheading:8782106-Kinetics,
pubmed-meshheading:8782106-Oocytes,
pubmed-meshheading:8782106-Patch-Clamp Techniques,
pubmed-meshheading:8782106-Protons,
pubmed-meshheading:8782106-Receptors, Neurotransmitter,
pubmed-meshheading:8782106-Symporters,
pubmed-meshheading:8782106-Xenopus laevis
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pubmed:year |
1996
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pubmed:articleTitle |
Interaction of L-cysteine with a human excitatory amino acid transporter.
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pubmed:affiliation |
Vollum Institute, Oregon Health Sciences University, Portland 97201, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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