Ionotropic glutamate receptors (iGluRs) mediate rapid excitatory neurotransmission in the mammalian CNS. They can be subdivided into three major groups, the AMPA/GluA, NMDA/GluN, and kainate/GluK receptors (KARs) (1, 2).
mRNAs coding for glutamate receptors are substrates for an adenosine deaminase acting on RNA (ADAR) that increases the diversity of these proteins (3). KARs can be found at pre- and postsynaptic sites and are composed of five different subunits: GluK1, GluK2 and GluK3 can form homomeric receptors whereas GluK4 and GluK5 form heteromeric receptors with GluK1-3 (4).