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Human brain neurons express a novel splice variant of excitatory amino acid transporter 5 ( hEAAT5v )
Author(s) -
Lee Aven,
Balcar Vladimir J.,
McCombe Pamela,
Pow David V.
Publication year - 2020
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.24907
Subject(s) - biology , glutamate receptor , glutamatergic , excitatory postsynaptic potential , neuroscience , transporter , gabaergic , microbiology and biotechnology , glutamate aspartate transporter , inhibitory postsynaptic potential , excitatory amino acid transporter , receptor , biochemistry , gene
Excitatory amino acid transporter 5 (EAAT5) is a protein that is known to be alternately spliced and to be abundantly expressed in the retina by populations of neurons including photoreceptors and bipolar cells. EAAT5 acts as a slow glutamate transporter and also as glutamate‐gated chloride channel, the chloride conductance being large enough for EAAT5 to serve functionally as an “inhibitory” glutamate receptor. However, there has been a long‐standing view that the classically spliced form of EAAT5 is not abundant or widespread in the brain and so it has not been extensively investigated in the literature. We recently identified a human‐specific splicing form of EAAT5 that was not expressed by rodents but was shown to be a functional glutamate transporter. We have examined the expression of this form of EAAT5, hEAAT5v at the mRNA, and protein level in human brain, and show that populations of human cortical pyramidal neurons and cerebellar Purkinje cells show significant expression of hEAAT5v. Accordingly, we infer that EAAT5 may well be a player in modulating neuronal function in the human brain and propose that its localization in both glutamatergic and GABAergic neurons could be compatible with a role in influencing intracellular chloride and thereby neuronal parameters such as membrane potential rather than acting as a presynaptic glutamate transporter.