Excitatory amino acid transporter 1
Protein found in humans
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Excitatory amino acid transporter 1 (EAAT1) is a protein that, in humans, is encoded by the SLC1A3 gene.[5] EAAT1 is also often called the GLutamate ASpartate Transporter 1 (GLAST-1).
EAAT1 is predominantly expressed in the plasma membrane, allowing it to remove glutamate from the extracellular space.[6] It has also been localized in the inner mitochondrial membrane as part of the malate-aspartate shuttle.[7]
Mechanism
EAAT1 functions in vivo as a homotrimer.[8] EAAT1 mediates the transport of glutamic and aspartic acid with the cotransport of three Na+ and one H+ cations and counter transport of one K+ cation. This co-transport coupling (or symport) allows the transport of glutamate into cells against a concentration gradient.[9]
"Diagram Illustrating the Malate-Aspartate Shuttle Pathway". (Glutamate aspartate transporter labeled at bottom center.)
Expression of SLC1A3 in the Bergmann glia fibers. Mouse brain at 7th postnatal day, sagittal section; GENSAT database.
Tissue distribution
EAAT1 is expressed throughout the CNS,[10] and is highly expressed in astrocytes and Bergmann glia in the cerebellum.[11][12] In the retina, EAAT1 is expressed in Muller cells.[13] EAAT1 is also expressed in a number of other tissues including cardiac myocytes.[7]
Clinical significance
It is associated with type 6 episodic ataxia.[14] EAAT1 expression may also be associated with osteoarthritis.[15]