GRIA2
Description
The GRIA2 (glutamate ionotropic receptor AMPA type subunit 2) is a protein-coding gene located on chromosome 4.
Glutamate ionotropic receptor AMPA type subunit 2 (Glutamate receptor 2, or GluR-2) is a protein that in humans is encoded by the GRIA2 (or GLUR2) gene and it is a subunit found in the AMPA receptors.
== Function == Glutamate receptors are the predominant excitatory neurotransmitter receptors in the mammalian brain and are activated in a variety of normal neurophysiologic processes. This gene product belongs to a family of glutamate receptors that are sensitive to alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA), called AMPA receptors, and function as ligand-activated cation channels. These channels are assembled from a combination of 4 subunits, encoded by 4 genes (GRIA1-4). The subunit encoded by this gene (GRIA2) is subject to RNA editing which renders the receptor that it becomes part of impermeable to calcium ions (Ca2+). Human and animal studies suggest that the RNA editing is essential for normal brain function, and defective RNA editing of this gene may be relevant to the etiology of amyotrophic lateral sclerosis (ALS). Alternative splicing, resulting in transcript variants encoding different isoforms, has been noted for this gene, which includes the generation of flip and flop isoforms that vary in their signal transduction properties.
== Interactions == GRIA2 has been shown to interact with SPTAN1, GRIP1 and PICK1.
== RNA editing == Several ion channels and neurotransmitters receptors pre-mRNA as substrates for ADARs. This includes 5 subunits of the glutamate receptor ionotropic AMPA glutamate receptor subunits (Glur2, Glur3, Glur4) and kainate receptor subunits (Glur5, Glur6).
GRIA2 encodes a glutamate receptor that acts as a ligand-gated ion channel in the central nervous system, playing a crucial role in excitatory synaptic transmission. L-glutamate, an excitatory neurotransmitter, binds to GRIA2, triggering a conformational change that opens the cation channel, converting chemical signals into electrical impulses. The receptor then quickly desensitizes, entering a temporary inactive state with the agonist bound. However, in the presence of CACNG4, CACNG7, or CACNG8, resensitization occurs, characterized by a delayed increase in current flow with continuous glutamate application. Through complex formation with NSG1, GRIP1, and STX12, GRIA2 regulates the intracellular fate of AMPAR and directs the GRIA2 subunit towards recycling and membrane targeting.
GRIA2 is also known as GLUR2, GLURB, GluA2, GluR-K2, HBGR2, NEDLIB, gluR-2, gluR-B.
