Excitatory amino acid transporter 5, a retinal glutamate transporter coupled to a chloride conductance.

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Arriza JL, Eliasof S, Kavanaugh MP, Amara SG

Excitatory amino acid transporter 5, a retinal glutamate transporter coupled to a chloride conductance.

Proc Natl Acad Sci U S A. 1997 Apr 15;94(8):4155-60.

PubMed ID

9108121 [ View in PubMed

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Abstract

Although a glutamate-gated chloride conductance with the properties of a sodium-dependent glutamate transporter has been described in vertebrate retinal photoreceptors and bipolar cells, the molecular species underlying this conductance has not yet been identified. We now report the cloning and functional characterization of a human excitatory amino acid transporter, EAAT5, expressed primarily in retina. Although EAAT5 shares the structural homologies of the EAAT gene family, one novel feature of the EAAT5 sequence is a carboxy-terminal motif identified previously in N-methyl-D-aspartate receptors and potassium channels and shown to confer interactions with a family of synaptic proteins that promote ion channel clustering. Functional properties of EAAT5 were examined in the Xenopus oocyte expression system by measuring radiolabeled glutamate flux and two-electrode voltage clamp recording. EAAT5-mediated L-glutamate uptake is sodium- and voltage-dependent and chloride-independent. Transporter currents elicited by glutamate are also sodium- and voltage-dependent, but ion substitution experiments suggest that this current is largely carried by chloride ions. These properties of EAAT5 are similar to the glutamate-elicited chloride conductances previously described in retinal neurons, suggesting that the EAAT5-associated chloride conductance may participate in visual processing.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Glutamic acid	Excitatory amino acid transporter 5	Protein	Humans	Unknown	Not Available	Details

Polypeptides

Name	UniProt ID
Excitatory amino acid transporter 5	O00341	Details