Regulation of Kv2.1 Channels by Kv9.1 Variants
<b>Background/Objectives:</b> Kv2 channels have important conducting and nonconducting functions and are regulated by their co-assembly with ‘silent’ Kv subunits, including Kv9.1. Kv9.1 is co-expressed with Kv2 channels in sensory neurons, and a common allele that changes Ile489 to Val i...
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2025-05-01
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| author | Hedaythul Choudhury Muruj Barri Kay Osborn Mohan Rajasekaran Marina Popova Owen S. Wells Edward B. Stevens Ruth D. Murrell-Lagnado |
| author_facet | Hedaythul Choudhury Muruj Barri Kay Osborn Mohan Rajasekaran Marina Popova Owen S. Wells Edward B. Stevens Ruth D. Murrell-Lagnado |
| author_sort | Hedaythul Choudhury |
| collection | DOAJ |
| description | <b>Background/Objectives:</b> Kv2 channels have important conducting and nonconducting functions and are regulated by their co-assembly with ‘silent’ Kv subunits, including Kv9.1. Kv9.1 is co-expressed with Kv2 channels in sensory neurons, and a common allele that changes Ile489 to Val in human Kv9.1 is associated with pain hypersensitivity in patients. The mechanism responsible for this association remains unknown, but we hypothesise that these two variants differ in their regulation of Kv2.1 properties, and this is what we set out to test. <b>Methods:</b> Expression was carried out using HEK293 cells, OHeLa cells, and primary cultures of hippocampal neurons, and the biophysical and trafficking properties of homomeric and heteromeric channels were assessed by confocal fluorescence microscopy and patch clamp analysis. <b>Results:</b> Both Kv9.1Ile and Kv9.1Val were retained within the endoplasmic reticulum when expressed individually, but when co-expressed with Kv2.1, they co-localised with Kv2.1 within the surface clusters. Both variants reduced the surface expression of Kv2.1 channels and the size of channel clusters, with Kv9.1Val producing a greater reduction in surface expression in both the HeLa cells and neurons. They both caused a similar hyperpolarising shift in the voltage dependence of channel activation and inactivation. Concatamers of Kv2.1 and Kv9.1 suggested that both 3:1 and 2:2 ratios of Kv2.1 to Kv9.1 were permitted, although 2:2 resulted in lower surface expression and function. <b>Conclusions:</b> The Ile489Val substitution in Kv9.1 does not disrupt its ability to co-assemble with Kv2 channels, nor its effects on the voltage-dependence of channel gating, but it did produce a greater reduction in the Kv2.1 surface expression, suggesting that this underlies its association with pain hypersensitivity. |
| format | Article |
| id | doaj-art-5f55cd51b8de460c9bbf8b219ae653ca |
| institution | Kabale University |
| issn | 2227-9059 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | MDPI AG |
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| series | Biomedicines |
| spelling | doaj-art-5f55cd51b8de460c9bbf8b219ae653ca2025-08-20T03:47:52ZengMDPI AGBiomedicines2227-90592025-05-01135111910.3390/biomedicines13051119Regulation of Kv2.1 Channels by Kv9.1 VariantsHedaythul Choudhury0Muruj Barri1Kay Osborn2Mohan Rajasekaran3Marina Popova4Owen S. Wells5Edward B. Stevens6Ruth D. Murrell-Lagnado7School of Life Sciences, University of Sussex, Brighton BN1 9QG, UKSchool of Life Sciences, University of Sussex, Brighton BN1 9QG, UKSchool of Life Sciences, University of Sussex, Brighton BN1 9QG, UKSchool of Life Sciences, University of Sussex, Brighton BN1 9QG, UKSchool of Life Sciences, University of Sussex, Brighton BN1 9QG, UKSchool of Life Sciences, University of Sussex, Brighton BN1 9QG, UKMetrion Biosciences, Building 2 Granta Centre, Granta Park, Cambridge CB21 6AL, UKSchool of Life Sciences, University of Sussex, Brighton BN1 9QG, UK<b>Background/Objectives:</b> Kv2 channels have important conducting and nonconducting functions and are regulated by their co-assembly with ‘silent’ Kv subunits, including Kv9.1. Kv9.1 is co-expressed with Kv2 channels in sensory neurons, and a common allele that changes Ile489 to Val in human Kv9.1 is associated with pain hypersensitivity in patients. The mechanism responsible for this association remains unknown, but we hypothesise that these two variants differ in their regulation of Kv2.1 properties, and this is what we set out to test. <b>Methods:</b> Expression was carried out using HEK293 cells, OHeLa cells, and primary cultures of hippocampal neurons, and the biophysical and trafficking properties of homomeric and heteromeric channels were assessed by confocal fluorescence microscopy and patch clamp analysis. <b>Results:</b> Both Kv9.1Ile and Kv9.1Val were retained within the endoplasmic reticulum when expressed individually, but when co-expressed with Kv2.1, they co-localised with Kv2.1 within the surface clusters. Both variants reduced the surface expression of Kv2.1 channels and the size of channel clusters, with Kv9.1Val producing a greater reduction in surface expression in both the HeLa cells and neurons. They both caused a similar hyperpolarising shift in the voltage dependence of channel activation and inactivation. Concatamers of Kv2.1 and Kv9.1 suggested that both 3:1 and 2:2 ratios of Kv2.1 to Kv9.1 were permitted, although 2:2 resulted in lower surface expression and function. <b>Conclusions:</b> The Ile489Val substitution in Kv9.1 does not disrupt its ability to co-assemble with Kv2 channels, nor its effects on the voltage-dependence of channel gating, but it did produce a greater reduction in the Kv2.1 surface expression, suggesting that this underlies its association with pain hypersensitivity.https://www.mdpi.com/2227-9059/13/5/1119Kv2 potassium channelspainneuronsfluorescence imagingpatch clamp electrophysiology |
| spellingShingle | Hedaythul Choudhury Muruj Barri Kay Osborn Mohan Rajasekaran Marina Popova Owen S. Wells Edward B. Stevens Ruth D. Murrell-Lagnado Regulation of Kv2.1 Channels by Kv9.1 Variants Biomedicines Kv2 potassium channels pain neurons fluorescence imaging patch clamp electrophysiology |
| title | Regulation of Kv2.1 Channels by Kv9.1 Variants |
| title_full | Regulation of Kv2.1 Channels by Kv9.1 Variants |
| title_fullStr | Regulation of Kv2.1 Channels by Kv9.1 Variants |
| title_full_unstemmed | Regulation of Kv2.1 Channels by Kv9.1 Variants |
| title_short | Regulation of Kv2.1 Channels by Kv9.1 Variants |
| title_sort | regulation of kv2 1 channels by kv9 1 variants |
| topic | Kv2 potassium channels pain neurons fluorescence imaging patch clamp electrophysiology |
| url | https://www.mdpi.com/2227-9059/13/5/1119 |
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