Ionotropic glutamate receptor
IPR015683
Definition
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 PMID: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 PMID:20808886. The ionotropic glutamate receptor family mediates most forms of excitatory synaptic transmission in the mammalian CNS. These channels also are required for synaptic plasticity and learning. Glutamate receptors have been divided into AMPA, kainate, and NMDA subtypes based on differences in agonist response. NMDA receptors require both membrane depolarisation and glutamate-binding to open and are key regulators of long-term potentiation in the mammalian brain. AMPA and kainate receptors mediate fast synaptic transmission in the CNS. A fourth subfamily of glutamate receptors, delta, has recently been identified. The function of the delta family in neuronal signalling is unknown. Approximately 30 glutamate receptor genes are present in Drosophila, compared with 15 in Caenorhabditis elegans. Invertebrate glutamate receptors can be subdivided into kainate (15 genes in flies, four in worms), AMPA (three genes in both), NMDA (one type 1 and one type 2 gene in both species), and delta subfamilies (four genes in both) on the basis of sequence similarities with mammalian counterparts. In addition, several novel subtypes are present for which no mammalian homologues have been identified, though several show low similarity with the Arabidopsis Glur5 glutamate receptor. Mammalian NMDA receptors are tetramers containing two type 1 and two type 2 subunits. The genes found in worms and flies suggest conservation of this subunit structure in invertebrates. The Drosophila NMDA type 1 gene is expressed in brain. Genetic analysis in flies should reveal whether NMDA receptors have a universal role in cellular mechanisms of learning. Mutational analysis has been described for the Drosophila receptors GluR2A and GluR2B, which are involved in synaptic transmission at the larval neuromuscular junction.
18 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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