Single-channel properties of recombinant AMPA receptors depend on RNA editing, splice variation, and subunit composition

Geoffrey T. Swanson, Sunjeev K. Kamboj, Stuart G. Cull-Candy*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

370 Scopus citations

Abstract

Non-NMDA glutamate receptor subunits of the AMPA-preferring subfamily combine to form ion channels with heterogeneous functional properties. We have investigated the effects of RNA editing at the Q/R site, splice variation of the 'flip/flop' cassette, and multimeric subunit assembly on the single-channel conductance and kinetic properties of the recombinant AMPA receptors formed from GluR2 and GluR4 expressed in HEK 293 cells. We found that AMPA receptor single-channel conductance was dependent on the Q/R site editing state of the subunits comprising the channel. Calcium-permeable (unedited) channels had resolvable single-channel events with main conductance states of 7-8 pS, whereas fully edited GluR2 channels had very low conductances of ~300 fS (estimated from noise analysis). Additionally, the flip splice variant of GluR4 conferred agonist-dependent conductance properties reminiscent of those found for a subset of AMPA receptors in cultured cerebellar granule cells. These results provide a description of the single-channel properties of certain recombinant AMPA receptors and suggest that the single-channel conductance may be determined by the expression of edited GluR2 subunits in neurons.

Original languageEnglish (US)
Pages (from-to)58-69
Number of pages12
JournalJournal of Neuroscience
Volume17
Issue number1
DOIs
StatePublished - 1997

Keywords

  • AMPA receptor
  • RNA editing
  • alternative splicing
  • glutamate receptor
  • patch-clamp electrophysiology
  • single-channel conductance

ASJC Scopus subject areas

  • Neuroscience(all)

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