Glutamate transporter

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.

The EAATs are membrane-bound secondary transporters that superficially resemble ion channels.[1] These transporters play the important role of regulating concentrations of glutamate in the extracellular space by transporting it along with other ions across cellular membranes.[2] After glutamate is released as the result of an action potential, glutamate transporters quickly remove it from the extracellular space to keep its levels low, thereby terminating the synaptic transmission.[1][3]

Without the activity of glutamate transporters, glutamate would build up and kill cells in a process called excitotoxicity, in which excessive amounts of glutamate acts as a toxin to neurons by triggering a number of biochemical cascades. The activity of glutamate transporters also allows glutamate to be recycled for repeated release.[4]

  1. ^ a b Ganel R, Rothstein JD (1999). "Chapter 15, Glutamate transporter dysfunction and neuronal death". In Monyer, Hannah, Gabriel A. Adelmann, Jonas, Peter (eds.). Ionotropic glutamate receptors in the CNS. Berlin: Springer. pp. 472–493. ISBN 3-540-66120-4.
  2. ^ Zerangue, N, Kavanaugh, MP (1996). "Flux coupling in a neuronal glutamate transporter". Nature. 383 (6601): 634–37. Bibcode:1996Natur.383..634Z. doi:10.1038/383634a0. PMID 8857541. S2CID 4266755.
  3. ^ Shigeri Y, Seal RP, Shimamoto K (2004). "Molecular pharmacology of glutamate transporters, EAATs and VGLUTs". Brain Res. Brain Res. Rev. 45 (3): 250–65. doi:10.1016/j.brainresrev.2004.04.004. PMID 15210307. S2CID 41057787.
  4. ^ Zou JY, Crews FT (2005). "TNF alpha potentiates glutamate neurotoxicity by inhibiting glutamate uptake in organotypic brain slice cultures: neuroprotection by NF kappa B inhibition". Brain Res. 1034 (1–2): 11–24. doi:10.1016/j.brainres.2004.11.014. PMID 15713255. S2CID 54316877.