High Affinity Transport of Taurine by the Drosophila Aspartate Transporter dEAAT2.
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| Title: | High Affinity Transport of Taurine by the Drosophila Aspartate Transporter dEAAT2. |
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| Authors: | Thérèse# Besson, Marie1, Ré, Diane B.2, Moulin, Matthieu1, Birman, Serge1 birman@ibdm.univ-mrs.fr |
| Source: | Journal of Biological Chemistry. 2/25/2005, Vol. 280 Issue 8, p6621-6626. 6p. 2 Charts, 6 Graphs. |
| Subjects: | Taurine, Drosophila, Biological transport, Proteins, Excitatory amino acids, Cell membranes, Proteomics, Biochemistry |
| Abstract: | Excitatory amino acid transporters (EAATs) are structurally related plasma membrane proteins known to mediate the Na+/K+-dependent uptake of the amino acids L-glutamate and DL-aspartate. In the nervous system, these proteins contribute to the clearance of glutamate from the synaptic cleft and maintain excitatory amino acid concentrations below excitotoxic levels. Two homologues exist in Drosophila melanogaster, dEAAT1 and dEAAT2, which are specifically expressed in the nervous tissue. We previously reported that dEAAT2 shows unique substrate discrimination as it mediates high affinity transport of aspartate but not glutamate. We now show that dEAAT2 can also transport the amino acid taurine with high affinity, a property that is not shared by two other transporters of the same family, Drosophila dEAAT1 and human hEAAT2. Taurine transport by dEAAT2 was efficiently blocked by an EAAT antagonist but not by inhibitors of the structurally unrelated mammalian taurine transporters. Taurine and aspartate are transported with similar Km and relative efficacy and behave as mutually competitive inhibitors. dEAAT2 can mediate either net uptake or the hetero-exchange of its two substrates, both being dependent on the presence of Na+ ions in the external medium. Interestingly, hetero-exchange only occurs in one preferred substrate orientation, i.e. with taurine transported inwards and aspartate outwards, suggesting a mechanism of transinhibition of aspartate uptake by intracellular taurine. Therefore, dEAAT2 is actually an aspartate/taurine transporter. Further studies of this protein are expected to shed light on the role of taurine as a candidate neuromodulator and cell survival factor in the Drosophila nervous system. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Biological Chemistry is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 16375847 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: High Affinity Transport of Taurine by the Drosophila Aspartate Transporter dEAAT2. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Thérèse#+Besson%2C+Marie%22">Thérèse# Besson, Marie</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Ré%2C+Diane+B%2E%22">Ré, Diane B.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Moulin%2C+Matthieu%22">Moulin, Matthieu</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Birman%2C+Serge%22">Birman, Serge</searchLink><relatesTo>1</relatesTo><i> birman@ibdm.univ-mrs.fr</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Biological+Chemistry%22">Journal of Biological Chemistry</searchLink>. 2/25/2005, Vol. 280 Issue 8, p6621-6626. 6p. 2 Charts, 6 Graphs. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Taurine%22">Taurine</searchLink><br /><searchLink fieldCode="DE" term="%22Drosophila%22">Drosophila</searchLink><br /><searchLink fieldCode="DE" term="%22Biological+transport%22">Biological transport</searchLink><br /><searchLink fieldCode="DE" term="%22Proteins%22">Proteins</searchLink><br /><searchLink fieldCode="DE" term="%22Excitatory+amino+acids%22">Excitatory amino acids</searchLink><br /><searchLink fieldCode="DE" term="%22Cell+membranes%22">Cell membranes</searchLink><br /><searchLink fieldCode="DE" term="%22Proteomics%22">Proteomics</searchLink><br /><searchLink fieldCode="DE" term="%22Biochemistry%22">Biochemistry</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Excitatory amino acid transporters (EAATs) are structurally related plasma membrane proteins known to mediate the Na+/K+-dependent uptake of the amino acids L-glutamate and DL-aspartate. In the nervous system, these proteins contribute to the clearance of glutamate from the synaptic cleft and maintain excitatory amino acid concentrations below excitotoxic levels. Two homologues exist in Drosophila melanogaster, dEAAT1 and dEAAT2, which are specifically expressed in the nervous tissue. We previously reported that dEAAT2 shows unique substrate discrimination as it mediates high affinity transport of aspartate but not glutamate. We now show that dEAAT2 can also transport the amino acid taurine with high affinity, a property that is not shared by two other transporters of the same family, Drosophila dEAAT1 and human hEAAT2. Taurine transport by dEAAT2 was efficiently blocked by an EAAT antagonist but not by inhibitors of the structurally unrelated mammalian taurine transporters. Taurine and aspartate are transported with similar Km and relative efficacy and behave as mutually competitive inhibitors. dEAAT2 can mediate either net uptake or the hetero-exchange of its two substrates, both being dependent on the presence of Na+ ions in the external medium. Interestingly, hetero-exchange only occurs in one preferred substrate orientation, i.e. with taurine transported inwards and aspartate outwards, suggesting a mechanism of transinhibition of aspartate uptake by intracellular taurine. Therefore, dEAAT2 is actually an aspartate/taurine transporter. Further studies of this protein are expected to shed light on the role of taurine as a candidate neuromodulator and cell survival factor in the Drosophila nervous system. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Biological Chemistry is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1074/jbc.M412440200 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 6 StartPage: 6621 Subjects: – SubjectFull: Taurine Type: general – SubjectFull: Drosophila Type: general – SubjectFull: Biological transport Type: general – SubjectFull: Proteins Type: general – SubjectFull: Excitatory amino acids Type: general – SubjectFull: Cell membranes Type: general – SubjectFull: Proteomics Type: general – SubjectFull: Biochemistry Type: general Titles: – TitleFull: High Affinity Transport of Taurine by the Drosophila Aspartate Transporter dEAAT2. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Thérèse# Besson, Marie – PersonEntity: Name: NameFull: Ré, Diane B. – PersonEntity: Name: NameFull: Moulin, Matthieu – PersonEntity: Name: NameFull: Birman, Serge IsPartOfRelationships: – BibEntity: Dates: – D: 25 M: 02 Text: 2/25/2005 Type: published Y: 2005 Identifiers: – Type: issn-print Value: 00219258 Numbering: – Type: volume Value: 280 – Type: issue Value: 8 Titles: – TitleFull: Journal of Biological Chemistry Type: main |
| ResultId | 1 |
