High impact information on SLC1A7

• Functional properties of EAAT5 were examined in the Xenopus oocyte expression system by measuring radiolabeled glutamate flux and two-electrode voltage clamp recording [1].
• Excitatory amino acid transporter 5, a retinal glutamate transporter coupled to a chloride conductance [1].
• EAAT5-mediated L-glutamate uptake is sodium- and voltage-dependent and chloride-independent [1].
• 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 [1].
• We now report the cloning and functional characterization of a human excitatory amino acid transporter, EAAT5, expressed primarily in retina [1].

Biological context of SLC1A7

• New alleles at the AAAT-repeat were found in one NF1 family and in three CEPH families giving a mutation rate for this AAAT-repeat of 0.36% per allele, which is one of the highest detected for a microsatellite locus [2].
• Base sequence specific binding of DST was also found for the 1:1 complex formation at the 4-base-paired sites, with AAAA, TTTT, ATTT, and AAAT sequences exhibiting the highest binding affinities [3].
• MPE-Fe(EDTA) footprinting of a novel monocationic bis-furan lexitropsin 6 on a HindIII/EcoRI restriction fragment of pBR322 DNA revealed a series of four-base binding sites (all 5'----3') of (primary) TGTA, TGAA, AAAT, ACAA, TTAT, and (secondary) CTAA, TCGT, TGTA, GTCA, and GGTT [4].

Anatomical context of SLC1A7

• Since the glutamate transporter EAAT5 is also expressed in terminals of rod photoreceptor terminals these data indicate that rod photoreceptors express two glutamate transporters with distinct properties [5].
• D-aspartate released by Müller cells was strongly accumulated into cone photoreceptors which are known to express GLT-1, and into rod photoreceptors which we demonstrate here to express the retina specific glutamate transporter EAAT5 (excitatory amino transporter 5) [6].
• Studies of carriers expressed on neurons, Purkinje cells and photoreceptor cells (EAAT3, EAAT4 and EAAT5, respectively) suggest more subtle roles for these subtypes in regulating excitability and signalling [7].

References