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1295  structures 872  species 0  interactions 17215  sequences 316  architectures

Family: Lig_chan (PF00060)

Summary: Ligand-gated ion channel

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This is the Wikipedia entry entitled "Ionotropic glutamate receptor". More...

Ionotropic glutamate receptor Edit Wikipedia article

PDB 1s50 EBI.jpg
x-ray structure of the glur6 ligand binding core (s1s2a) in complex with glutamate at 1.65 a resolution
Pfam clanCL0030
OPM superfamily177
OPM protein3kg2

Ionotropic glutamate receptors (iGluRs) are ligand-gated ion channels that are activated by the neurotransmitter glutamate.[1] They mediate the majority of excitatory synaptic transmission throughout the central nervous system and are key players in synaptic plasticity, which is important for learning and memory. iGluRs have been divided into four subtypes on the basis of their ligand binding properties (pharmacology) and sequence similarity: AMPA receptors, kainate receptors, NMDA receptors and delta receptors (see below).[2]

AMPA receptors are the main charge carriers during basal transmission, permitting influx of sodium ions to depolarise the postsynaptic membrane. NMDA receptors are blocked by magnesium ions and therefore only permit ion flux following prior depolarisation. This enables them to act as coincidence detectors for synaptic plasticity. Calcium influx through NMDA receptors leads to persistent modifications in the strength of synaptic transmission.[3][4]

iGluRs are tetramers (they are formed of four subunits). All subunits have a shared architecture with four domain layers: two extracellular clamshell domains called the N-terminal domain (NTD) and ligand-binding domain (LBD; which binds glutamate), the transmembrane domain (TMD) that forms the ion channel, and an intracellular C-terminal domain (CTD).[5]

Human proteins/genes encoding iGluR subunits

AMPA receptors: GluA1/GRIA1; GluA2/GRIA2; GluA3/GRIA3; GluA4/GRIA4;

delta receptors: GluD1/GRID1; GluD2/GRID2;

kainate receptors: GluK1/GRIK1; GluK2/GRIK2; GluK3/GRIK3; GluK4/GRIK4; GluK5/GRIK5;

NMDA receptors: GluN1/GRIN1; GluN2A/GRIN2A; GluN2B/GRIN2B; GluN2C/GRIN2C; GluN2D/GRIN2D; GluN3A/GRIN3A; GluN3B/GRIN3B;


  1. ^ Traynelis SF, Wollmuth LP, McBain CJ, Menniti FS, Vance KM, Ogden KK, Hansen KB, Yuan H, Myers SJ, Dingledine R (September 2010). "Glutamate receptor ion channels: structure, regulation, and function". Pharmacol. Rev. 62 (3): 405–496. doi:10.1124/pr.109.002451. PMC 2964903. PMID 20716669.
  2. ^ Collingridge GL, Olsen RW, Peters J, Spedding M (January 2009). "A nomenclature for ligand-gated ion channels". Neuropharmacology. 56 (1): 2–5. doi:10.1016/j.neuropharm.2008.06.063. PMC 2847504. PMID 18655795.
  3. ^ Bliss TV, Collingridge GL (January 1993). "A synaptic model of memory: long-term potentiation in the hippocampus". Nature. 361 (6407): 31–39. doi:10.1038/361031a0. PMID 8421494.
  4. ^ Citri A, Malenka RC (January 2008). "Synaptic plasticity: multiple forms, functions, and mechanisms". Neuropsychopharmacology. 33 (1): 18–41. doi:10.1038/sj.npp.1301559. PMID 17728696.
  5. ^ Traynelis SF, Wollmuth LP, McBain CJ, Menniti FS, Vance KM, Ogden KK, Hansen KB, Yuan H, Myers SJ, Dingledine R (September 2010). "Glutamate receptor ion channels: structure, regulation, and function". Pharmacol. Rev. 62 (3): 405–496. doi:10.1124/pr.109.002451. PMC 2964903. PMID 20716669.
This article incorporates text from the public domain Pfam and InterPro: IPR001320

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Ligand-gated ion channel Provide feedback

This family includes the four transmembrane regions of the ionotropic glutamate receptors and NMDA receptors.

Literature references

  1. Tong G, Shepherd D, Jahr CE; , Science 1995;267:1510-1512.: Synaptic desensitization of NMDA receptors by calcineurin. PUBMED:7878472 EPMC:7878472

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR001320

There are three classes of ionotropic glutamate receptors (iGluRs), namely NMDA (N-methyl-D-aspartate), AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole-4-propionic acid) and kainate receptors. They are believed to play critical roles in synaptic plasticity. At many synapses in the brain, transient activation of NMDA receptors leads to a persistent modification in the strength of synaptic transmission mediated by AMPA receptors and kainate receptors can act as the induction trigger for long-term changes in synaptic transmission [ PUBMED:10580501 ].

Ionotropic glutamate receptors (iGluRs) are a highly conserved family of ligand-gated ion channels present in animals, plants, and bacteria, which are best characterised for their roles in synaptic communication in vertebrate nervous systems [ PUBMED:14977400 ]. A variant subfamily of iGluRs, the Ionotropic Receptors (IRs), consist of non-glutamate-binding chemosensory receptors first identified in Drosophila melanogaster. They function in detecting odors and tastants [ PUBMED:20808886 ].

Gene Ontology

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Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan Ion_channel (CL0030), which has the following description:

This superfamily contains a diverse range of ion channels that share a pair of transmembrane helices in common. This clan is classified as the VIC (Voltage-gated Ion Channel) superfamily in TCDB.

The clan contains the following 7 members:

Ion_trans Ion_trans_2 IRK KdpA Lig_chan PKD_channel TrkH


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Curation and family details

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Seed source: Blastp NMZ1_HUMAN
Previous IDs: lig_chan;
Type: Family
Sequence Ontology: SO:0100021
Author: Bateman A , Sonnhammer ELL
Number in seed: 43
Number in full: 17215
Average length of the domain: 254.70 aa
Average identity of full alignment: 21 %
Average coverage of the sequence by the domain: 31.15 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null --hand HMM SEED
search method: hmmsearch -Z 57096847 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 30.8 30.8
Trusted cut-off 30.8 30.8
Noise cut-off 30.7 30.7
Model length: 149
Family (HMM) version: 28
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Species distribution

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Archea Archea Eukaryota Eukaryota
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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Lig_chan domain has been found. There are 1295 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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