| Background |
AMPA- (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid), kainate-, and NMDA- (N-methyl-D-aspartate) receptors are the three main families of ionotropic glutamate-gated ion channels. AMPA receptors (AMPARs) are comprised of four subunits (GluR 1-4), which assemble as homo- or hetero-tetramers to mediate the majority of fast excitatory transmissions in the central nervous system. AMPARs are implicated in synapse formation, stabilization, and plasticity In contrast to GluR 2-containing AMPARs, AMPARs that lack GluR 2 are permeable to calcium Post-transcriptional modifications (alternative splicing, nuclear RNA editing) and post-translational modifications (glycosylation, phosphorylation) result in a very large number of permutations, fine-tuning the kinetic properties of AMPARs. Research studies have implicated activity changes in AMPARs in a variety of diseases including Alzheimer’s, amyotrophic lateral sclerosis (ALS), stroke, and epilepsyGluR 4 containing AMPARs are found in synapses and GluR 4 delivery to synapses and cell surface expression is mediated through phosphorylation of Ser842 by PKA or PKC.
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