Cargando…
Stoichiometry of δ subunit containing GABA(A) receptors
BACKGROUND AND PURPOSE: Although the stoichiometry of the major synaptic αβγ subunit-containing GABA(A) receptors has consensus support for 2α:2β:1γ, a clear view of the stoichiometry of extrasynaptic receptors containing δ subunits has remained elusive. Here we examine the subunit stoichiometry of...
Autores principales: | , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John wiley & Sons Ltd
2014
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3925037/ https://www.ncbi.nlm.nih.gov/pubmed/24206220 http://dx.doi.org/10.1111/bph.12514 |
_version_ | 1782303803037450240 |
---|---|
author | Patel, B Mortensen, M Smart, T G |
author_facet | Patel, B Mortensen, M Smart, T G |
author_sort | Patel, B |
collection | PubMed |
description | BACKGROUND AND PURPOSE: Although the stoichiometry of the major synaptic αβγ subunit-containing GABA(A) receptors has consensus support for 2α:2β:1γ, a clear view of the stoichiometry of extrasynaptic receptors containing δ subunits has remained elusive. Here we examine the subunit stoichiometry of recombinant α4β3δ receptors using a reporter mutation and a functional electrophysiological approach. EXPERIMENTAL APPROACH: Using site-directed mutagenesis, we inserted a highly characterized 9′ serine to leucine mutation into the second transmembrane (M2) region of α4, β3 and δ subunits that increases receptor sensitivity to GABA. Whole-cell, GABA-activated currents were recorded from HEK-293 cells co-expressing different combinations of wild-type (WT) and/or mutant α4(L297S), β3(L284S) and δ(L288S) subunits. KEY RESULTS: Recombinant receptors containing one or more mutant subunits showed increased GABA sensitivity relative to WT receptors by approximately fourfold, independent of the subunit class (α, β or δ) carrying the mutation. GABA dose–response curves of cells co-expressing WT subunits with their respective L9′S mutants exhibited multiple components, with the number of discernible components enabling a subunit stoichiometry of 2α, 2β and 1δ to be deduced for α4β3δ receptors. Varying the cDNA transfection ratio by 10-fold had no significant effect on the number of incorporated δ subunits. CONCLUSIONS AND IMPLICATIONS: Subunit stoichiometry is an important determinant of GABA(A) receptor function and pharmacology, and δ subunit-containing receptors are important mediators of tonic inhibition in several brain regions. Here we demonstrate a preferred subunit stoichiometry for α4β3δ receptors of 2α, 2β and 1δ. |
format | Online Article Text |
id | pubmed-3925037 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | John wiley & Sons Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-39250372014-09-22 Stoichiometry of δ subunit containing GABA(A) receptors Patel, B Mortensen, M Smart, T G Br J Pharmacol Research Papers BACKGROUND AND PURPOSE: Although the stoichiometry of the major synaptic αβγ subunit-containing GABA(A) receptors has consensus support for 2α:2β:1γ, a clear view of the stoichiometry of extrasynaptic receptors containing δ subunits has remained elusive. Here we examine the subunit stoichiometry of recombinant α4β3δ receptors using a reporter mutation and a functional electrophysiological approach. EXPERIMENTAL APPROACH: Using site-directed mutagenesis, we inserted a highly characterized 9′ serine to leucine mutation into the second transmembrane (M2) region of α4, β3 and δ subunits that increases receptor sensitivity to GABA. Whole-cell, GABA-activated currents were recorded from HEK-293 cells co-expressing different combinations of wild-type (WT) and/or mutant α4(L297S), β3(L284S) and δ(L288S) subunits. KEY RESULTS: Recombinant receptors containing one or more mutant subunits showed increased GABA sensitivity relative to WT receptors by approximately fourfold, independent of the subunit class (α, β or δ) carrying the mutation. GABA dose–response curves of cells co-expressing WT subunits with their respective L9′S mutants exhibited multiple components, with the number of discernible components enabling a subunit stoichiometry of 2α, 2β and 1δ to be deduced for α4β3δ receptors. Varying the cDNA transfection ratio by 10-fold had no significant effect on the number of incorporated δ subunits. CONCLUSIONS AND IMPLICATIONS: Subunit stoichiometry is an important determinant of GABA(A) receptor function and pharmacology, and δ subunit-containing receptors are important mediators of tonic inhibition in several brain regions. Here we demonstrate a preferred subunit stoichiometry for α4β3δ receptors of 2α, 2β and 1δ. John wiley & Sons Ltd 2014-02 2014-01-24 /pmc/articles/PMC3925037/ /pubmed/24206220 http://dx.doi.org/10.1111/bph.12514 Text en Copyright © 2013 The British Pharmacological Society |
spellingShingle | Research Papers Patel, B Mortensen, M Smart, T G Stoichiometry of δ subunit containing GABA(A) receptors |
title | Stoichiometry of δ subunit containing GABA(A) receptors |
title_full | Stoichiometry of δ subunit containing GABA(A) receptors |
title_fullStr | Stoichiometry of δ subunit containing GABA(A) receptors |
title_full_unstemmed | Stoichiometry of δ subunit containing GABA(A) receptors |
title_short | Stoichiometry of δ subunit containing GABA(A) receptors |
title_sort | stoichiometry of δ subunit containing gaba(a) receptors |
topic | Research Papers |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3925037/ https://www.ncbi.nlm.nih.gov/pubmed/24206220 http://dx.doi.org/10.1111/bph.12514 |
work_keys_str_mv | AT patelb stoichiometryofdsubunitcontaininggabaareceptors AT mortensenm stoichiometryofdsubunitcontaininggabaareceptors AT smarttg stoichiometryofdsubunitcontaininggabaareceptors |