Smelt, CLC;
Sanders, VR;
Puinean, AM;
Lansdell, SJ;
Goodchild, J;
Millar, NS;
(2021)
Agonist and antagonist properties of an insect GABA-gated chloride channel (RDL) are influenced by heterologous expression conditions.
PLoS One
, 16
(7)
, Article e0254251. 10.1371/journal.pone.0254251.
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Abstract
Pentameric ligand-gated ion channels (pLGICs) activated by the inhibitory neurotransmitter γ-aminobutyric acid (GABA) are expressed widely in both vertebrate and invertebrate species. One of the best characterised insect GABA-gated chloride channels is RDL, an abbreviation of 'resistance to dieldrin', that was originally identified by genetic screening in Drosophila melanogaster. Here we have cloned the analogous gene from the bumblebee Bombus terrestris audax (BtRDL) and examined its pharmacological properties by functional expression in Xenopus oocytes. Somewhat unexpectedly, the sensitivity of BtRDL to GABA, as measured by its apparent affinity (EC50), was influenced by heterologous expression conditions. This phenomenon was observed in response to alterations in the amount of cRNA injected; the length of time that oocytes were incubated before functional analysis; and by the presence or absence of a 3' untranslated region. In contrast, similar changes in expression conditions were not associated with changes in apparent affinity with RDL cloned from D. melanogaster (DmRDL). Changes in apparent affinity with BtRDL were also observed following co-expression of a chaperone protein (NACHO). Similar changes in apparent affinity were observed with an allosteric agonist (propofol) and a non-competitive antagonist (picrotoxinin), indicating that expression-depended changes are not restricted to the orthosteric agonist binding site. Interestingly, instances of expression-dependent changes in apparent affinity have been reported previously for vertebrate glycine receptors, which are also members of the pLGIC super-family. Our observations with BtRDL are consistent with previous data obtained with vertebrate glycine receptors and indicates that agonist and antagonist apparent affinity can be influenced by the level of functional expression in a variety of pLGICs.
| Type: | Article |
|---|---|
| Title: | Agonist and antagonist properties of an insect GABA-gated chloride channel (RDL) are influenced by heterologous expression conditions |
| Location: | United States |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1371/journal.pone.0254251 |
| Publisher version: | https://doi.org/10.1371/journal.pone.0254251 |
| Language: | English |
| Additional information: | © 2021 Smelt et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/). |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences > Neuro, Physiology and Pharmacology |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10131151 |
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