Excitatory amino acid transporter 3 (EAAT3), is a protein that in humans is encoded by the SLC1A1 gene. [5] [6]
EAAT3 is expressed on the plasma membrane of neurons, specifically on the dendrites and axon terminals. [7]
Excitatory amino acid transporter 3 is a member of the high-affinity glutamate transporters which plays an essential role in transporting glutamate across plasma membranes in neurons. In the brain, excitatory amino acid transporters are crucial in terminating the postsynaptic action of the neurotransmitter glutamate, and in maintaining extracellular glutamate concentrations below neurotoxic levels. EAAT3 also transports aspartate, and mutations in this gene are thought to cause dicarboxylic aminoaciduria, also known as glutamate-aspartate transport defect. [6] EAAT3 is also the major route of neuronal cysteine uptake. Cysteine is a component of the major antioxidant glutathione, and mice lacking EAAT3 exhibit reduced levels of glutathione in neurons, increased oxidative stress, and age-dependent loss of neurons, especially neurons of the substantia nigra. A meta-analysis identified a small but significant association between a polymorphism of the gene SLC1A1 and Obsessive-Compulsive Disorder. [8]
Glutamate transporters are a family of neurotransmitter transporter proteins that move glutamate – the principal excitatory neurotransmitter – across a membrane. The family of glutamate transporters is composed of two primary subclasses: the excitatory amino acid transporter (EAAT) family and vesicular glutamate transporter (VGLUT) family. In the brain, EAATs remove glutamate from the synaptic cleft and extrasynaptic sites via glutamate reuptake into glial cells and neurons, while VGLUTs move glutamate from the cell cytoplasm into synaptic vesicles. Glutamate transporters also transport aspartate and are present in virtually all peripheral tissues, including the heart, liver, testes, and bone. They exhibit stereoselectivity for L-glutamate but transport both L-aspartate and D-aspartate.
Excitatory amino-acid transporter 5 (EAAT5) is a protein that in humans is encoded by the SLC1A7 gene.
Excitatory amino-acid transporter 4 (EAAT4) is a protein that in humans is encoded by the SLC1A6 gene.
Neurotransmitter transporters are a class of membrane transport proteins that span the cellular membranes of neurons. Their primary function is to carry neurotransmitters across these membranes and to direct their further transport to specific intracellular locations. There are more than twenty types of neurotransmitter transporters.
Excitatory amino acid transporter 1 (EAAT1) is a protein that, in humans, is encoded by the SLC1A3 gene. EAAT1 is also often called the GLutamate ASpartate Transporter 1 (GLAST-1).
Glutamate [NMDA] receptor subunit epsilon-2, also known as N-methyl D-aspartate receptor subtype 2B, is a protein that in humans is encoded by the GRIN2B gene.
Excitatory amino acid transporter 2 (EAAT2) also known as solute carrier family 1 member 2 (SLC1A2) and glutamate transporter 1 (GLT-1) is a protein that in humans is encoded by the SLC1A2 gene. Alternatively spliced transcript variants of this gene have been described, but their full-length nature is not known.
Glutamate ionotropic receptor AMPA type subunit 2 is a protein that in humans is encoded by the GRIA2 gene and it is a subunit found in the AMPA receptors.
PRA1 family protein 3 is a protein that in humans is encoded by the ARL6IP5 gene.
Glutamate [NMDA] receptor subunit 3A is a protein that in humans is encoded by the GRIN3A gene.
Glutamate [NMDA] receptor subunit epsilon-4 is a protein that in humans is encoded by the GRIN2D gene.
Glutamate [NMDA] receptor subunit epsilon-3 is a protein that in humans is encoded by the GRIN2C gene.
Glutamate [NMDA] receptor subunit 3B is a protein that in humans is encoded by the GRIN3B gene.
Cystine/glutamate transporter is an antiporter that in humans is encoded by the SLC7A11 gene.
Potassium-chloride transporter member 5 is a neuron-specific chloride potassium symporter responsible for establishing the chloride ion gradient in neurons through the maintenance of low intracellular chloride concentrations. It is a critical mediator of synaptic inhibition, cellular protection against excitotoxicity and may also act as a modulator of neuroplasticity. Potassium-chloride transporter member 5 is also known by the names: KCC2 for its ionic substrates, and SLC12A5 for its genetic origin from the SLC12A5 gene in humans.
Vesicular glutamate transporter 3 (VGLUT3) is a protein that in humans is encoded by the SLC17A8 gene.
Sodium-dependent neutral amino acid transporter B(0)AT2 is a protein that in humans is encoded by the SLC6A15 gene.
Dicarboxylic aminoaciduria is a rare form of aminoaciduria which is an autosomal recessive disorder of urinary glutamate and aspartate due to genetic errors related to transport of these amino acids. Mutations resulting in a lack of expression of the SLC1A1 gene, a member of the solute carrier family, are found to cause development of dicarboxylic aminoaciduria in humans. SLC1A1 encodes for EAAT3 which is found in the neurons, intestine, kidney, lung, and heart. EAAT3 is part of a family of high affinity glutamate transporters which transport both glutamate and aspartate across the plasma membrane.
An excitatory amino acid reuptake inhibitor (EAARI) is a type of drug which inhibits the reuptake of the excitatory neurotransmitters glutamate and aspartate by blocking one or more of the excitatory amino acid transporters (EAATs).
In neuroscience, glutamate refers to the anion of glutamic acid in its role as a neurotransmitter: a chemical that nerve cells use to send signals to other cells. It is by a wide margin the most abundant excitatory neurotransmitter in the vertebrate nervous system. It is used by every major excitatory function in the vertebrate brain, accounting in total for well over 90% of the synaptic connections in the human brain. It also serves as the primary neurotransmitter for some localized brain regions, such as cerebellum granule cells.
In general, EAATs 1 and 2 are found predominantly in astrocytes, EAAT3 in neurons, EAAT4 in Purkinje cells, and EAAT5 expression is restricted to the retina (Danbolt, 2001). The dependence of EAAT3 internalization on the DAT also suggests that the two transporters might be internalized together. We found that EAAT3 and DAT are expressed in the same cells, as well as in axons and dendrites. However, the subcellular co-localization of the two neurotransmitter transporters remains to be established definitively by high resolution electron microscopy.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.