The Glutamate-gated Ion Channel (GIC) Family of Neurotransmitter Receptors (TC# 1.A.10) is a family of large proteins that belong the Voltage-Gated Ion Channel (VIC) Superfamily. Members of this family are characterized from both eukaryotes and bacteria and function as both ion channels and receptors. A representative list of proteins belonging to the GIC family can be found in the Transporter Classification Database.[1]
Types of GIC channels
The GIC channels are divided into three types:
- α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-selective glutamate receptors,
- kainate-selective glutamate receptors, and
- N-methyl-D-aspartate (NMDA)-selective glutamate receptors.
They possess large N-terminal, extracellular glutamate-binding domains that are homologous to the periplasmic glutamine and glutamate receptors (TC# 3.A.1.3.2 and TC# 3.A.1.3.4, respectively) of ABC-type uptake permeases (TC# 3.A.1) of Gram-negative bacteria. The different channel (receptor) types exhibit distinct ion selectivities and conductance properties. The NMDA-selective large conductance channels are highly permeable to monovalent cations and Ca2+. The AMPA- and kainate-selective ion channels are permeable primarily to monovalent cations with only low permeability to Ca2+.[2][3][4]
Structure
Members of the GIC family are homo or heterotetrameric complexes in which each of the 4 subunits is of 800-1000 amino acyl residues in length and exhibits between 3 and 6 transmembrane segments (TMSs).[5] There are several crystal structures available for members of the GIC family.
GluR-K1 aka GRIA1 aka GLUR1: PDB: 2AWW, 3SAJ
GluR-D aka GRIA4 aka GLUR4: PDB: 3EN3, 3EPE, 3FAS, 3FAT, 3KEI, etc.
Glutamate receptor, ionotropic kainate 1 aka GluR5 aka Grik1: PDB: 1TXF, 1VSO, 2F36, 2OJT, 2QS4, etc.
Glutamate receptor, ionotropic kainate 2: PDB: 2NR1, 3BYA, 2A5S, 3JPW, etc.
Glutamate receptor 2: PDB: 1S50, 1S7Y, 1S9T, 1SD3, 3QLT, etc.
Glutamate [NMDA] receptor subunit zeta-1 aka NR1: PDB: 4JWX, 4NF5, 3QEM, 2HQW, etc
NMDA glutamate receptor subunit: PDB: 3QEK, 3QEL, 3QEM
GluRO aka SLR1257: PDB: 1II5, 1IIT, 1IIW
Function
These channels are responsible for the fast excitatory synaptic transmission and ion selectivity in the brain.[4]
The generalized transport reaction catalyzed by GIC family channels is:
Me+ (or Me2+) (out) ⇌ Me+ (or Me2+) (in).
See also
References
- ↑ "1.A.10 The Glutamate-gated Ion Channel (GIC) Family of Neurotransmitter Receptors". TCDB. Retrieved 2016-04-16.
- ↑ Furukawa, Hiroyasu; Singh, Satinder K.; Mancusso, Romina; Gouaux, Eric (2005-11-10). "Subunit arrangement and function in NMDA receptors". Nature 438 (7065): 185–192. doi:10.1038/nature04089. ISSN 1476-4687. PMID 16281028.
- ↑ Dutta, Anindita; Krieger, James; Lee, Ji Young; Garcia-Nafria, Javier; Greger, Ingo H.; Bahar, Ivet (2015-09-01). "Cooperative Dynamics of Intact AMPA and NMDA Glutamate Receptors: Similarities and Subfamily-Specific Differences". Structure (London, England: 1993) 23 (9): 1692–1704. doi:10.1016/j.str.2015.07.002. ISSN 1878-4186. PMC 4558295. PMID 26256538.
- 1 2 Regan, Michael C.; Romero-Hernandez, Annabel; Furukawa, Hiro (2015-08-01). "A structural biology perspective on NMDA receptor pharmacology and function". Current Opinion in Structural Biology 33: 68–75. doi:10.1016/j.sbi.2015.07.012. ISSN 1879-033X. PMC 4641752. PMID 26282925.
- ↑ Mayer, Mark L. (2006-03-23). "Glutamate receptors at atomic resolution". Nature 440 (7083): 456–462. doi:10.1038/nature04709. ISSN 1476-4687. PMID 16554805.
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