Neuronal and glial glutamate transporters possess an SH-based redox regulatory mechanism

Détails

ID Serval
serval:BIB_815546D17C8C
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Neuronal and glial glutamate transporters possess an SH-based redox regulatory mechanism
Périodique
European Journal of Neuroscience
Auteur(s)
Trotti  D., Rizzini  B. L., Rossi  D., Haugeto  O., Racagni  G., Danbolt  N. C., Volterra  A.
ISSN
0953-816X (Print)
Statut éditorial
Publié
Date de publication
06/1997
Volume
9
Numéro
6
Pages
1236-43
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Jun
Résumé
Glutamate uptake into nerve cells and astrocytes via high-affinity transporters controls the extracellular glutamate concentration in the brain, with major implications for physiological excitatory neurotransmission and the prevention of excitotoxicity. We report here that three recently cloned rat glutamate transporter subtypes, viz. EAAC1 (neuronal), GLT1 and GLAST (glial), possess a redox-sensing property, undergoing opposite functional changes in response to oxidation or reduction of reactive sulphydryls present in their structure. In particular, thiol oxidation with 5,5'-dithio-bis(2-nitrobenzoic) acid (DTNB) and disulphide reduction with dithiothreitol (DTT) result, respectively, in reduced and increased uptake capacity by a preparation of partially purified brain transporters as well as by the three recombinant proteins reconstituted into liposomes. In this model system, EAAC1, GLT1 and GLAST react similarly to DTT/DTNB exposures despite their different contents of cysteines, suggesting that only the conserved residues might be involved in redox modulation. Redox sensitivity is a property of the glutamate transporters also when present in their native cell environment. Thus, by using cultured cortical astrocytes and the whole-cell patch-clamp technique we were able to observe dynamic increase and decrease of the glutamate uptake current in response to application of DTT and DTNB in sequence. Moreover, in the same paradigm, DDT-reversible current inhibition was observed with hydrogen peroxide instead of DTNB, indicating that the SH-based redox modulatory site is targeted by endogenous oxidants and might constitute an important physiological or pathophysiological regulatory mechanism of glutamate uptake in vivo.
Mots-clé
ATP-Binding Cassette Transporters/chemistry/*metabolism Amino Acid Transport System X-AG Animals Astrocytes/metabolism Brain/cytology Brain Chemistry/physiology Carrier Proteins/chemistry/*metabolism Cells, Cultured DNA, Complementary/biosynthesis Electrophysiology Excitatory Amino Acid Transporter 1 Excitatory Amino Acid Transporter 3 Glutamate Plasma Membrane Transport Proteins Liposomes Neuroglia/*metabolism Neurons/*metabolism Oxidation-Reduction Patch-Clamp Techniques Plasmids Rats Sulfhydryl Compounds/*metabolism *Symporters
Pubmed
Web of science
Création de la notice
24/01/2008 15:37
Dernière modification de la notice
03/03/2018 18:47
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