The KA-2 subunit of excitatory amino acid receptors shows widespread expression in brain and forms ion channels with distantly related subunits

Neuron. 1992 Apr;8(4):775-85. doi: 10.1016/0896-6273(92)90098-x.


A new ionotropic glutamate receptor subunit termed KA-2, cloned from rat brain cDNA, exhibits high affinity for [3H]kainate (KD approximately 15 nM). KA-2 mRNA is widely expressed in embryonic and adult brain. Homomeric KA-2 expression does not generate agonist-sensitive channels, but currents are observed when KA-2 is coexpressed with GluR5 or GluR6 subunits. Specifically, coexpression of GluR5(R) and KA-2 produces channel activity, whereas homomeric expression of either subunit does not. Currents through heteromeric GluR5(Q)/KA-2 channels show more rapid desensitization and different current-voltage relations when compared with GluR5(Q) currents. GluR6/KA-2 channels are gated by AMPA, which fails to gate homomeric GluR6 receptor channels. These results suggest possible in vivo partnership relations for high affinity kainate receptors.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Brain / physiology*
  • Cloning, Molecular
  • Gene Expression
  • Ion Channels / genetics
  • Ion Channels / ultrastructure*
  • Ligands
  • Macromolecular Substances
  • Molecular Sequence Data
  • Nucleic Acid Hybridization
  • Oligonucleotide Probes / chemistry
  • RNA, Messenger / genetics
  • Rats
  • Receptors, Glutamate
  • Receptors, Kainic Acid
  • Receptors, Neurotransmitter / genetics
  • Receptors, Neurotransmitter / physiology*
  • Sequence Alignment


  • Ion Channels
  • Ligands
  • Macromolecular Substances
  • Oligonucleotide Probes
  • RNA, Messenger
  • Receptors, Glutamate
  • Receptors, Kainic Acid
  • Receptors, Neurotransmitter

Associated data

  • GENBANK/X59996
  • GENBANK/Z11581